Amazon Stonehenge or Calçoene megalithic observatory is megalithic structure located in Amapa state, Brazil. It consists of 127 blocks of granite, each up to 4 metres tall, standing upright in circles at the bank of river on a hilltop. During the excavations there have been found numerous ceramic fragments and whole urns with charred bones, soil and red pigment.[3]
Based on ceramic fragments found nearby, archaeologists believe this structure is between 500 and 2000 years old.[1][2][4]
On the shortest day of the year in the northern hemisphere, December 21, the shadow of one of the blocks disappears when the sun is directly above it.[4] The rock seems to be placed at angle so that the shadow is possibly small throughout the day[3]. It is this block's alignment with the December solstice that leads archaeologists to believe the site was once an astronomical observatory and that they may also be looking at the remnants of a sophisticated culture.[4]