Chinese Pyramids occupy 2000 square kilometers, in the locality where Chinese military and space research is based. The pyramids had been kept in secret until 2003. China officially confirmed the existence of these pyramids in 2004. You can access the area only if you have the permit. Most of the 90 pyramids will have been preserved until 2050 for the purpose of research. It is estimated that the pyramids are 5000 years old. The most mysterious is the Great White Pyramid , which is up to 300m high. The other pyramids are 35m to 90m high.