This was discovered in 2003-2004. Archaeologists unearthed a Middle Taosi period semi-round foundation just beside southern wall of the Middle Taosi enclosure, which could be used for astronomical observations. The structure consists of an outer semi-ring-shaped path, and a semi-round rammed-earth platform with a diameter of about 60 m. The platform is 42m in diameter and over 1000 sq m in area, and can be reconstructed as a three-level altar.

On the other hand, some Western scholars assert that emperor Yao was a mythical figure.