In May 2006, reports emerged of an "Amazon Stonehenge", found in the Amazon Basin, in Brazil. It is comprised of 127 blocks of granite, each 3 metres (10 feet) high, standing upright in even circles in an open field, according to ABC News and Mongabay.com. According to MSNBC, some of the blocks are has high as 9 feet tall, and crown a grassy hilltop. Based on ceramic fragments found nearby, archaeologists believe this structure is between 500 and 2000 years old.



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.[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.



Source: Wikipedia