Nabta Playa, 6800 years old (Sahara) Southwestern EGYPT. Alignments with the bright stars Sirius, Arcturus, Alpha Centauri, and the Belt of Orion have been confirmed. The calendar circle is a 12-foot-wide arrangement of slabs about 18inches long, most of them lying down. Narrow slabs approximately align with the summer solstice, near the beginning of the rainy season. Two pairs of upright stones stand directly across the circle from each other, defining a view that would have displayed sunrise at the summer solstice. The circle also contains two different pairs of standing stones that defined a north-south orientation.