In Finland, there is a kind of tradition of good-natured rivalry between different cities, most notably between Helsinki (the most populous city), Tampere (the third most populous city) and Turku (the fifth most populous city). The inhabitants of any two of these cities can be said to have rivalry between them, because of different reasons.
Inhabitants of Helsinki are well aware that their city is by far the most populous and most famous in Finland. This can make them seem arrogant and contemptuous to people in other cities, especially Tampere and Turku. Some people in Helsinki refer to Kehä III, the outermost of the two ring roads surrounding the Greater Helsinki area, as a "wolf border" (susiraja), outside which there is no civilisation. Outsiders refer to inside of Kehä III as the biggest psychiatric hospital in Finland.
Those from Helsinki view people from Turku either as naïve and simple-minded, or arrogant and impudent. In Helsinki they have a saying that the only good thing in Turku is the highway leading to Helsinki. Another version is a joke: What is the best place in Turku? - Turku Railway Station. You can take there a Pendolino to Helsinki. It is also said, that on that same highway, the only place where you can do an U-turn is at the "Turku" sign. Inhabitants of Turku see Helsinkians as presumptuous and parvenu.
Rivalry between Helsinki and Tampere mainly concerns ice hockey. Both cities have two famous ice hockey teams - HIFK and Jokerit in Helsinki, Ilves and Tappara in Tampere. Ice hockey fans in each city say that the teams in the other city are worthless. Also football is important, HJK Helsinki, the most successful club in Finland is hated especially in smaller cities but also in Turku and Tampere.
Finally, Turku and Tampere also share a rivalry. Turku is far older and has had a greater impact on history and Finnish culture, whereas Tampere is more populous and has a greater significance as an industrial city, lately also in the Information Technology business. Inhabitants in both Turku and Tampere view the people in the other city as uncivilised. A popular joke in Turku asks why children in Tampere have a flat nose. The answer is that there is a Turku midwife working in a Tampere hospital. After delivering a child, the midwife holds him/her into the glass of a window and says: "Look now, child. That way is Turku, there is civilisation." Students across Tampere go to the border of Turku and nail wooden nails to the ground, in order to make the city drift off the mainland someday, and also go to the center of the city and jump there, so that the city would someday sink back to the sea.
Still, one of the most famous rivalries in Finland is between cities of Pori and Rauma in Satakunta Region (Western Province). One of the things that make the difference is the language which is very different although they're only 50 km apart. Rauma has its own dialect while Pori has a very different kind of lingo. Especially in ice hockey there is a huge rivalry: Pori has a two-times champion Ässät and Rauma a one-time champion Lukko. Local derbies tend to be very hectic. Inhabitants also like to make very humiliating jokes about each other. Although it would be very wise to make more co-operation between the cities, it is likely an impossible task. Still, one step forward was taken when ports of both cities started planning more co-operation between one another.