Vast, unidentified structures in the Gobi Desert have spotted by Google Earth, raising questions about what China may be building in an area they use for its military, space and nuclear programmes.

The bizarre structures seen by Google Earth satellites are located at the border of the Gansu and Xinjiang provinces. Some are less than 100 miles from Jiuquan, the headquarters of China's space programme.

Two of the images show a series of connected reflective rectangles up to a mile long that are clearly visible from space.

A third picture shows huge concentric circles, with three jets parked at their centre. Another image shows a series of metallic squares with what looks likes the remains of exploded vehicles scattered around.

Theories have begun to emerge that the strange structures and outlines are replicas of street layouts, some of which even claiming that they are similar to the layout of Washington DC.

Ding Xin military airbase, where China carries out its secret aircraft testing programme, is relatively close to where these structures lie around 400 miles away.

400 miles in the other direction is Lop Nur, the salt lakes where China tested 45 nuclear bombs between 1967 and 1995.

This has led some people to believe that these huge structures are built as optical test ranges for missiles.