The world’s oldest known astronomical site, Nabta Playa, was built in Africa and is 2,000 years older than Stonehenge. Located in the Sahara desert, the 7,000-year-old stone circle was used to track the summer solstice and the arrival of the annual monsoon season. – WTF Fun Facts
Source: Nabta Playa: The world’s first astronomical site was built in Africa | Astronomy.com