The 75,000-year-old Adam’s calendar is crobably the World’s oldest man-made structure.

Also referred to as “African Stonehenge,” Adam’s Calendar is a standing stone circle about 30 m in diameter in Mpumalanga, South Africa. Although uncertain, the structure is estimated to be 75,000 years old, making it the oldest man-made structure on Earth.

Even though there are numerous astronomical alignments at the site, Adam’s Calendar is probably the only fully functional and almost intact megalithic stone calendar in the world.

According to the latest estimations, there are at least 100 000 stone circles throughout the mountains of South Africa.

Known as the Birthplace of the Sun, this enigmatic site first draw public attention in 2003 when the South African pilot Johan Heine started photographing the region.

The experts first thought that the ruins were the remains of cattle kraal "livestock enclosure" abandoned by the Bantu people around the 14th century.