Mysterious rings puzzle archaeologists at the tomb of Chinese empress

Chinese archaeologists are confounded by a group 10 huge rings at the site of the tomb of the country's only empress, Wu Zetian. The rings, ranging from 30 to 40 meters in diameter, were discovered when aerial photos were taken.

Researcher Qin Jianming said the largest ring has a diameter of 110 meters and is three meters thick and is a different color than the surrounding earth.

The tomb is located 80 kilometers northwest of Xi'an, capital of northwest China's Shaanxi Province. Wu Zetian ruled China for 50 years in the 7th century.