Cydonia is an area of Mars that generated a lot of interest and conspiracy theories when it was photographed by NASA’s Viking orbiter in 1976. The pictures appeared to show a number of peculiar anomalies including a series of pyramid shaped objects on the surface and a large structure that resembled a humanoid face.
In more recent years newer NASA Mars orbiters have returned additional photographs of the region showing that the ‘face’ was nothing more than a natural rock formation however the original pictures and the area itself are still under some considerable debate.