Border barrier

A border barrier is a separation barrier that runs along an international border. Such barriers are typically constructed for border control purposes, viz. to curb illegal immigration, human trafficking and smuggling.^[1][2]

In cases of a disputed or unclear border, erecting a barrier can serve as a de facto unilateral consolidation of a territorial claim.

Examples include the ancient Great Wall of China, a series of walls separating China from nomadic empires to the north and the modern Mexico–United States barrier.

List of current barriers

Note: The table can be sorted alphabetically or chronologically using the icon.

Name	Country	Built	Length (km)	Type
Belize-Guatemala	Belize	Proposed	N/A	Disputed Territory and Anti-illegal immigration
Botswana/Zimbabwe	Botswana and Zimbabwe	2003	500	Anti-illegal immigration
Brunei/Limbang	Brunei and Limbang	2005	20	Anti-illegal immigration
Bulgaria/Turkey	Bulgaria	2014	30	Anti-illegal immigration
Ceuta border fence	Spain	2001	8	Anti-illegal immigration
China/Hong Kong	Hong Kong	1960s -early	32	Anti-illegal immigration
Costa Rica/Nicaragua	Costa Rica	Proposed	N/A	Anti-illegal immigration
Chinese-Korean border fence	China and North Korea	Under construction	1,416	Anti-illegal immigration
Egypt-Gaza barrier	Egypt	1979, subterranean barrier under construction	3.1	Anti-terrorism and anti-illegal immigration
Estonia-Russia border fence	Estonia and Russia	Planned	106-108	anti-Russian intrusion, anti-illegal trade and anti-illegal immigration
Macedonia-Greece border	Macedonia
Malaysia-Thailand border	Thailand and Malaysia	Proposed	650	Anti-terrorism
Melilla border fence	Spain	1998	11	Anti-illegal immigration
Hungary–Serbia barrier	Hungary	2015	175	Anti-illegal immigration
Hungary–Croatia barrier	Hungary	2015	41	Anti-illegal immigration
Indo-Bangladeshi barrier	India	Under construction	3,268	Anti-illegal immigration
Indo-Burma barrier	India	Under construction	1,624	Anti-drug smuggling and anti-terrorism
Indian Kashmir barrier	India	2004	550	Anti-terrorism (disputed territory)
Iran-Pakistan barrier	Iran and Pakistan	Under construction	700	Anti-drug smuggling
Kazakh-Uzbekistan barrier	Kazakhstan and Uzbekistan	2006	45	Anti-drug smuggling
Korean Demilitarized Zone	North Korea and South Korea	1953	248	Conflict zone
Kruger National Park	South Africa and Mozambique	1975	120	Anti-illegal immigration
South Africa/Zimbabwe Border	South Africa	2000s	2900	Anti-illegal immigration, Anti-drug Smuggling, Anti Weapon Smuggling
Kuwait-Iraq barrier	Kuwait and Iraq	1991	193	Conflict zone
Pakistan-Afghanistan barrier	Pakistan	Proposed	2,400	Anti-terrorism
Saudi-Yemen barrier	Saudi Arabia and Yemen	2004	75	Anti-illegal immigration
Saudi-Iraq barrier	Saudi Arabia and Iraq	2006	900	Anti-illegal immigration and Conflict zone
Slovenia-Croatia barrier	Slovenia	under construction	N/A	Anti-illegal immigration
Turkmen-Uzbekistan barrier	Turkmenistan and Uzbekistan	2001	1,700	Anti-illegal immigration
Ukraine-Russia barrier	Ukraine and Russia	Under construction	2,000	Anti Weapon Smuggling and Conflict zone
United Arab Emirates-Oman barrier	United Arab Emirates and Oman	Under construction	410	Anti-illegal immigration
United States–Mexico barrier	United States	Under construction	3,360	Anti-illegal immigration and drug smuggling
Uzbek-Afghanistan barrier	Uzbekistan and Afghanistan	2001	209	Anti-illegal immigration
Uzbek-Kyrgyzstan barrier	Uzbekistan and Kyrgyzstan	1999	870	Conflict zone

Barriers by region

Africa

Botswana

In 2003, Botswana began building a 300-mile (480 km)-long electric fence along its border with Zimbabwe. The official reason for the fence is to stop the spread of foot-and-mouth disease among livestock. Zimbabweans argue that the height of the fence is clearly intended to keep out people. Botswana has responded that the fence is designed to keep out cattle, and to ensure that entrants have their shoes disinfected at legal border crossings. Botswana also argued that the government continues to encourage legal movement into the country. Zimbabwe was unconvinced, and the barrier remains a source of tension.^[3]

Egypt

The Rafah Border Crossing (Arabic: معبر رفح, Hebrew: מעבר רפיח) is an international border crossing at Palestinian-controlled Rafah between Egypt and the Gaza Strip. It was built by the Israeli and Egyptian governments after the 1979 Israel-Egypt Peace Treaty and confirmed after Israel's 1982 withdrawal from the Sinai Peninsula. It was managed by the Israel Airports Authority until it was evacuated on 11 September 2005 as part of Israel's unilateral disengagement plan, after which it fell on the European Union Border Assistance Mission Rafah (EUBAM) to monitor the crossing.

Morocco

The Moroccan Wall is an approximately 2,700 km-long structure, mostly a sand wall (or "berm"), running through the region of Western Sahara and the southeastern portion of Morocco. It acts as a barrier between the Moroccan-controlled areas (Southern Provinces) and the Polisario-controlled section of the territory - Free Zone or de facto the self-proclaimed Sahrawi Arab Democratic Republic that lies along its eastern and southern border.

According to maps from MINURSO^[4] or the UNHCR,^[5] part of the wall extends several kilometers into internationally recognized Mauritanian territory.

South Africa

In 1975 a security fence of 120 kilometres (75 mi) was erected by South Africa to keep the violent revolution in Mozambique from spilling into Kruger National Park.^[6] In 1990 it was reported:

“

Concern is growing in South Africa over the country's use of a lethal, 3,300 volt one amp electrified fence on its borders with Mozambique and Zimbabwe. According to a report recently published by the South African Catholic Bureau for Refugees, the fence has caused more deaths in three years than the Berlin Wall did in its entire history. Local people call the fence the 'Snake of Fire'. There have been calls by South African church leaders over the past months for the fence to be switched off permanently. Most of its victims have been women and children fleeing the war in Mozambique. The Berlin Wall resulted in 80 deaths over 28 years. Official figures provided by the South African Defence Force (SADF) indicate that 89 people were electrocuted at the fence between August 1986 and August 1989. Church leaders dispute these figures, and claim that the true figure is nearer 200 each year.[7]

”

On December 9, 2002, by the presidents of South Africa, Mozambique, and Zimbabwe signed a treaty authorizing the fence to be torn down in order to re-open the ancient elephant migration route between South Africa and Mozambique. The Great Limpopo Transfrontier Park of 35,000 square kilometres (14,000 sq mi) will connect the national parks of the three countries—South Africa's Kruger National Park, Mozambique's Limpopo National Park, and Zimbabwe's Gonarezhou National Park.^[8]

In 2005 it was reported that only a relatively small portion of the high-security border fence separating South Africa's Kruger National Park with Zimbabwe's Gonarezhou Park had been removed. Security concerns, especially about illegal immigrants and the smuggling of weapons and four-wheel-drive vehicles, have been hindering the removal of more sections of the border fence.^[9]

Americas

Brazil

Brazil has built huge concrete walls (up to 10 feet) serving as “eco-barriers’” to contain urban sprawl. Officials see it as a means of protecting the forest but critics maintain that it's a strategy for walling in and containing the city’s favelas (slums). The critics argue that the eco-barriers are a cover for cleaning up the city in preparation for the 2014 FIFA World Cup and the 2016 Summer Olympics.

United States

The United States has constructed a border barrier along 130 kilometres (81 mi) of its border with Mexico of 3,169 kilometres (1,969 mi) to prevent illegal immigration to the United States and to deter smuggling of contraband, particularly illegal drugs. There has been legislation in the U.S. Congress on lengthening the barrier, but progress has been slow due to lobbying and lack of funding.

The border along US and Canada does not have restrictive fencing and some areas a separated by a narrow strip with trees removed to show where the border lies. It is the longest unprotected border in the world. The border area is split between land and water crossing with Ontario with the latter.

US and Canadian law enforcement patrol near the border area and legally entry must be made from select border crossing points along the border. United States Border Patrol has about 300 agents deployed along this border.^[10] On the Canadian side Canada Border Services Agency is the agency responsible for patrols.

Asia

Afghanistan

In January 2006, Afghanistan's government decreed that the United Nations, the American embassy, and other foreign organizations in Kabul must clear concrete security barriers that protect their buildings. Most Kabul streets are full of security barriers and large concrete anti-blast blocks aimed at protecting against the insurgent and terrorist attacks that have risen in the past four years since the fall of the Taliban regime. The decree follows pressure from the newly formed Afghan parliament and public complaints over the heavy traffic jams caused by the barriers. The foreign groups are expressing concern and saying that the security situation does not permit that. The United Nations is one of the organizations concerned by the Afghan government's order. UN chief spokesman in Kabul Adrian Edwards said that security barriers are still required. "We are in a difficult security environment which certainly hasn't improved during 2005", Edwards said. "There have been a number of suicide attacks. Within the UN here, I think none of us would wish to be behind these barricades, we would prefer things could be open as we are in some other countries. However, there have been necessary for our security, that's why they are there." The Afghan government has said it is determined to remove all the barricades. The directive of the government says that "blocking the footpaths, streets, and roads is illegal" and that no one has the right to create obstructions, the only exception being the presidential palace.

Brunei

Brunei is building a security fence along its 20-km border with Limbang, Malaysia, to stop the flow of irregular migrants and smuggled goods.

China (Hong Kong and Macau Special Administrative Regions)

The People's Republic of China (PRC) has two Special Administrative Regions on its southeastern coast—Hong Kong and Macau, both of which maintain controlled intra-national borders with the neighbouring Guangdong province in Mainland China. An identity document is inspected when one crosses the border.

Hong Kong was a Dependent Territory of the UK until its sovereignty was handed over to the PRC in 1997, while Macau was a Special Territory of Portugal until its sovereignty was handed over to the PRC in 1999. Before the transfers of sovereignty back to the PRC, the Hong Kong–-Guangdong and Macau–Guangdong borders were regarded as international borders.

Under the principle of "One Country, Two Systems", the two Special Administrative Regions continue to maintain their own customs and immigration policies, which are independent of those in Mainland China after the handovers. Due to differences in the policies between the special administrative regions and the Mainland, the Hong Kong—Guandgong and Macau—Guangdong borders have been maintained in operation after the returns.

Hong Kong has a border stretching 32 km with the Shenzhen Special Economic Zone of Guangdong that features fences, thermal image sensors, lights and closed-circuit television. The border is also patrolled regularly by police (and previous by the British Army until a short time before the handover in 1997). Just south of Shenzhen River (the geographical delimitation of the border) is a strip of rural land with restricted access, the 28 km² Closed Area. Currently, the four road border crossings are located at Sha Tau Kok, Man Kam To, Lok Ma Chau and Shenzhen Bay, and a railway and traveller crossing is located at Lo Wu. The residents of the Hong Kong Special Administrative Region are required to have their Hong Kong ID Cards inspected by the Hong Kong Immigration Department and their Home Return Permits inspected by the Public Security Bureau of Guangdong when they cross the border. Travelers from other countries and regions are required to present their passports or other types of travel documents for immigration clearance at both Hong Kong immigration checkpoints and Mainland China immigration ports.

Macau has been maintaining a 340-metre controlled border with Zhuhai City in Guangdong with a crossing available at the Border Gate (built in 1870).^[11] The border crossing is equipped with 54 counters for travelers and 8 for vehicular traffic. Opened in 1999, Macau's Lotus Bridge supplemented what has been the only border crossing into mainland China through Border Gate. Both border crossings allow access to Zhuhai. Canal dos Patos, a former canal forms part of the border area along with Sun Yat-sen Municipal Park located to west of Border Gate area. Fencing along both sides of the canal restricts access to either side. Pagoda-like sentry towers are located along the Mainland China side of the border.

China (Mainland)

China, in October 2006, is also building a security barrier along its border with North Korea to prevent illegal immigrants.^[12]

India

Since the mid-1990s, India has been involved in the construction of some of the lengthiest border barriers along its international borders. Six of the nine countries neighboring India are classified as Least Developed Countries, and thus thousands of people from these countries—especially from Bangladesh and Burma—illegally immigrate into India.

The Indo-Bangladeshi barrier and Indo-Burma barrier are being built to check smuggling, illegal immigration, and infiltration by Islamist terrorists. The refugee crisis could also ensue should a climate catastrophe ravage South Asia.

In addition, India completed the construction of the Indian-Kashmir barrier, which runs along the Line of Control in Kashmir. The purpose of this barrier is to prevent infiltration by armed militants. Many Kashmiris both in Jammu and Kashmir of India and Azad Kashmir in Pakistan opposed the barrier since Kashmir is a disputed territory.

Iran

The Iran-Pakistan barrier wall is 700 kilometers long, which Iran claims is to stop the flow of illegal border crossings, stem the flow of drugs and prevent terror attacks. However, the Provincial Assembly of Balochistan, whose lands straddle the border region, strongly opposed the barrier as the wall would divide the Baloch people politically and socially, with trade and social activities being seriously impeded.

Leader of the Opposition, Kachkol Ali, said the governments of the two countries had not taken the Baloch into their confidence on this matter^[13] and demanded that construction be stopped immediately and he also appealed to the international community.^[14] Residents of the Sorap locality in the Mand area of western Mekran region in Balochistan province rely on edible goods from Iran for their livelihood but Iranian border security forces vacate the town. According to BBC, "The Balochistanis, who live on both sides of the border and in the area where both countries neighbour Afghanistan, have had their communities divided by the wall."^[15]

Israel

Due to Israel's specific security situation, as well as immigration concerns, border fences and walls have been utilized:

• Jerusalem: During the 1950s and 1960s a fortified separation barrier also divided much of Jerusalem to separate Jordanian and Israeli-controlled sectors of the city. It was pulled down in the immediate aftermath of the 1967 Six Day War, when the eastern part of the city came under Israeli rule. Currently, the route of the West Bank barrier in Jerusalem cuts off residents of the Jerusalem municipality from Jerusalem proper.^[16]
• Lebanon and Syria: Israel's borders with Lebanon and Syria have sophisticated security barriers, including electronic surveillance and warning systems. The barrier along the Lebanese border follows the lines of the 1949 Armistice and was laid down in coordination with the UN, the government anxious to make clear that it had withdrawn completely from Lebanese territory (excepting the ongoing dispute on the Shaba Farms).
  • The barrier on the Syrian border on the Golan Heights reflects the situation in the aftermath of the Yom Kippur War, when Israel retained the territory conquered in 1967 except for handing back the town of Kuneitra. The Syrian government has repeatedly demanded the return of the entire Golan, but has made no specific issue of Israel erecting a security barrier along the border as it presently stands.
• Egypt: Israel saw no need to fortify the Sinai Desert border with Egypt after the 1979 Israeli-Egyptian Peace Treaty. The fence along that border was always more a marker than an effective barrier, and has become rusty and swamped by shifting sand dunes. The porous border has become the scene of extensive drug trafficking and the smuggling of women, typically from Third World and East European countries, who are subsequently forced into prostitution, as well as the entry of various refugees, asylum-seekers and illegal immigrants from various African countries, notably Sudanese fleeing the genocide in Darfur and Erithreans fleeing due to compulsive military service. There were also isolated cases of infiltration by armed terrorists, and apprehension that they would increase. In December 2005 the government of Israel proposed building a £200 million security barrier along the Egyptian border, in 2013 Israel completed the bulk of the border with Egypt.
• Jordan: The border of Israel's territory with Jordan, mostly in the Arabah, is considered the most peaceful of the country's borders, due to traditional good relations with Jordan's Hashemite Dynasty. In addition to the Negev border, Israel and Jordan also share the West Bank's border with Jordan in the Jordan Valley. Along this border there is a security barrier with two purposes. It is designed to stop both infiltration from Jordan into the Israeli-controlled territory and the passage of West Bank Palestinians, uncontrolled by Israeli officials, into Jordan.
• The Israel–Gaza barrier involves a security barrier along Israel's 1949 Armistice lines. There was also the security barrier along the Gaza Strip's border with Egypt (originally Philadelphi Route, which later became the Egypt–Gaza barrier), erected when Israel was in direct military control of the area.

Korea

South Korea has constructed a border barrier between its territory and North Korea to obstruct any southward movement by the army of North Korea. The border features:

• Panmunjeom
• Military Demarcation Line
• Korean Demilitarized Zone

Kuwait

The United Nations has constructed a demilitarized zone to stop Iraq from re-invading Kuwait; Kuwait plans to install a new border barrier as well.

• Kuwait–Iraq barrier

Pakistan

In September 2005, Pakistan stated it has plans to build a 1,500-mile (2,400 km) fence along its border with Afghanistan to prevent Islamic insurgents and drug smugglers slipping between the two countries. Former Pakistani President Pervez Musharraf has subsequently offered to mine the border as well.^[17][18]

Russia

There is an electronic security barrier (ex-"Iron Curtain") along the old Soviet border. Also, a security barrier is on the border of Russia with Norway, Finland, China, Mongolia, and North Korea. There is no barrier on Russian territory along the border with Estonia, Latvia, Belarus, or Ukraine, but there are some barriers on the Estonian, Latvian sides. It was reported in 2005 that the Russian government was considering the construction of a security barrier along its internal border with Chechnya to combat terrorism.^[19]

Saudi Arabia

Saudi Arabia has begun construction of a border barrier or fence between its territory and Yemen to prevent the unauthorized movement of people and goods. The Yemenis have been a source of trouble for the Saudis for many years; the difference between the countries' economic situations means that many Yemenis head to Saudi Arabia to find work. Saudi Arabia does not have a barrier with its other neighbors in the Gulf Cooperation Council, whose economies are similarly wealthy.

• Saudi-Yemen barrier

In 2006 Saudi Arabia proposed constructing a security fence along the entire length of its desert border of 900 kilometres (560 mi) with Iraq in a multimillion-dollar project to secure the Kingdom's borders in order to improve internal security, control illegal immigration, and bolster its defences against external threats.^[20]

• Saudi-Iraq barrier

As of July 2009 it was reported that Saudis will pay $3.5 billion for security fence.^[21] The combined wall and ditch will be 600 miles long and include five layers of fencing, watch towers, night-vision cameras, and radar cameras and manned by 30,000 troops.^[22]

Thailand

Thailand plans to build a concrete fence along parts of its border with Malaysia to keep Muslim militants and dual citizens from crossing Thailand's southern border with Malaysia.

• Thai-Malay barrier

Turkey

Turkey announced a plan in July 2015 to build a 800-km (500-mi) wall along its border with Syria.^[23]

United Arab Emirates

The UAE is building a security barrier along its border with Oman.

• United Arab Emirates-Oman barrier

Uzbekistan

In 1999 Uzbekistan began constructing a barbed wire fence to secure its border with Kyrgyzstan.

• Uzbek-Kyrgyzstan barrier

In 2001 Uzbekistan fortified the fence with Afghanistan.

• Uzbek-Afghanistan barrier

Europe

Austria

In October 2015, during the European migrant crisis, Austrian interior minister Johanna Mikl-Leitner announced construction of up to 15 km long border barriers at several border crossings with Slovenia. It is to be constructed within days with the aim of the restoring order at the border. The barrier is to be guarded by Austrian police and Austrian Armed Forces^[24]

Bulgaria

Estonia

In August 2015, Estonia announced a plan to build a barrier on its border with Russia.^[25]

Greece

After having made an agreement with Frontex on the guard of the maritime borders of Greece with Turkey^[26] the Greek government decided a wall to be built at the land border with Turkey, the Evros River.^[27] These actions have been made as a reaction to the illegal immigration to Greece through the Greco-Turkish borders. These immigrants are originated from Asian and African states. From January to the beginning of November 2010, 32,500 illegal migrants were intercepted in a single 12.5-kilometer stretch of the Turkish-Greek border along the Evros River.^[28] Actually this site is the main entrance of illegal immigrants to the EU from the Asian continent.^[28] Illegal immigration is a current subject between the two countries.

Greece has constructed a barrier on the section of its land border with Turkey that is not separated by the Evros river, between October 2011 and December 2012.^[29]

Hungary

Hungary completed the construction of a 175-km wall between Hungary and Serbia in September 2015 and on the border with Croatia in October 2015 to stop illegal migration into the EU.^[30]

Macedonia

Macedonia began erecting a fence on its border with Greece in November 2015.^[31]

Northern Ireland

In Belfast, Derry, and other settlements in Northern Ireland, barriers called "peace lines" have been built to separate the two main communities. Their purpose is to minimize inter-communal violence between Irish nationalists/republicans (who mainly self-identify as Irish and/or Catholic) and unionists/loyalists (who mainly self-identify as British and/or Protestant). They were first built following the 1969 riots and beginning of the "Troubles". They have continued to be built and expanded since the Belfast Agreement of 1998. In 2008 a public discussion began about how and when the barriers could be removed.^[32] On 1 September 2011, Belfast City Council agreed to develop a strategy regarding the removal of peace walls.^[33] At the end of 2011 several local community initiatives resulted in several interface structures being opened for a trial period.^[34] In January 2012, the International Fund for Ireland launched a Peace Walls funding programme to support local communities who want to work towards removing the peace walls.^[35]

Slovenia

Slovenia began erecting a border barrier along its border with Croatia in 2015 to control illegal migration into the Schengen Area.^[36]

Spain

The European Union and Spain have constructed barriers between the Spanish exclaves of Ceuta and Melilla and Morocco to prevent illegal immigration and smuggling.

• Ceuta border fence
• Melilla border fence

Even though both the United Kingdom and Spain are part of the European Union, the border fence separating Gibraltar and Spain is still relevant because Gibraltar, a British Overseas Territory, is not part of the Schengen Area so remains outside of the customs union and VAT area. The border crossing is open twenty-four hours a day to facilitate customs collection by Spain.

Ukraine

Border barriers in history

Antiquity

• Hadrian's Wall
• Antonine Wall
• Great Wall of China
  • A counterpart wall to the Great Wall in the south called the Southern Great Wall was erected to protect and divide the Chinese from the "southern barbarians" called Miao (meaning barbaric and nomadic).^[37]
• Madukkarai Wall
• Great Wall of Gorgan

Middle Ages

• Cheolli Jangseong

Early modern period

• Zanja de Alsina, built in the 1870s along the southern frontier of Argentina
• Great Hedge of India, built by the British in 1803

Defunct barriers in modern times

• The Maginot Line, built between 1929 to 1938 by France on the French-German border as a defensive structure.
• Between Russia (Soviet Union) and Finland/Norway there was a fence on the Soviet side along the entire border (more than 1,000 km) during the Cold war. Along the Finnish border it was not so well guarded since Finland agreed to send back all Russians who escaped. The fence was located a few kilometers from the border, and still partly remains, even though the border controls are open now. Russian law still forbids crossing the border outside of a border station.
• Iron Curtain, including:
  • Berlin Wall
  • Inner German border
  • German-Czech Border
• Panama Canal fence

Other

• Limes Germanicus
• Limes Saxoniae
• Gates of Alexander
• Offa's Dyke
• Danevirke
• Götavirke
• Willow Palisade
• Zasechnaya cherta

See also

• Defensive walls
• List of fortifications
• List of walls
• List of cities with defensive walls
• Buffer zone
• Marches

References

External links

• Security Fences in The Atlantic Monthly
• Article about CityWalls on Erasmuspc
• "Obama's Border Fence", NOW on PBS, July 3, 2009.
• "Around Globe, Walls Spring Up to Divide Neighbors" Page Not Found, Reuters, April 30, 2007.
• Border to Border, Wall to Wall, Fence to Fence

Fortifications Ancient history Abatis Agger Broch Castra Castros Circular rampart City gate Crannog Ditch Defensive wall Faussebraye Gatehouse Gord Hill fort Limes Oppidum Palisade Promontory fort Rampart Ringfort (Rath) Refuge castle Stockade Sudis Trou de loup Vallum Laager (Wagon fort) Vitrified fort Post-classical history Albarrana tower Arrowslit Barbican Bartizan Bastion Battlement Bent entrance Bergfried Bretèche Bridge castle Bridge tower Butter-churn tower Caltrop Castle Chemin de ronde Chemise Cheval de frise Citadel Concentric castle Curtain Drawbridge Enceinte Embrasure Flanking tower Fortified buildings (church, house) Gate tower Gabion Glacis Guard tower Gulyay-gorod Half tower Hoarding Inner bailey Keep Kremlin (Detinets) L-plan castle Machicolation Merlon Moat Motte-and-bailey Murder-hole Neck ditch Outer bailey Peel tower Portcullis Postern Reduit Ringwork Quadrangular castle Shield wall Toll castle Tower castle Tower house Turret Wall tower Ward (Bailey) Watchtower Witch tower Yett Modern history 18th century and earlier Bastion Blockhouse Breastwork Canal Caponier Casemate Cavalier Counterguard Counterscarp Couvreface Coupure Covertway Crownwork Entrenchment Flèche Gorge Hornwork Lunette Orillon Ostrog Outwork Place-of-arms Polygonal fort Presidio (Spanish America) Punji sticks Ravelin Redan Redoubt Retrenchment Sandbag Scarp Sconce Schanze Sea fort Station Star fort Tenaille 19th century Barbed wire Barbette Border outpost Bunker Coastal artillery Gun turret Land battery Land mine Martello tower Outpost Trench warfare Sangar Wire obstacles 20th century Admiralty scaffolding Air-raid shelter Barbed tape Blast pen Blast shelter Blast wall Border barrier Bremer wall Concertina wire Defensive fighting position British "hedgehog" road block Czech hedgehog Dragon's teeth Electric fence Fallout shelter Fire support base Flak tower Hardened aircraft shelter Hesco bastion Main Line of Resistance Revetment Sentry gun Spider hole Underground hangar By topography Cave castle Hill castle Hill fort Hillside castle Hilltop castle Island castle Lowland castle Marsh castle Moated castle Promontory fort Ridge castle Rocca Rock castle Spur castle Water castle By role Hunting lodge Imperial castle Kaiserpfalz Lustschloss Ordensburg Refuge castle Toll castle By design Bridge castle Concentric castle Quadrangular castle Tower castle See also: Category