Photos of Elysium Planitia taken by the Mars Reconnaissance Orbiter (MRO) of NASA has alien enthusiasts believe that proof of the existence of walled cities on Mars has been found.

Elysium Planitia is a plain located near the equator of the red planet lying south of Elysium and is known as the largest volcanic region of Mars. The photographs show aerial views of what appears to be domes, led enthusiasts to believe that these are signs that there was once life on the planet. More skeptical ones believe they are mere geological formations, nothing more.

The photographs also show the domes to be eroded and surrounded by almost circular rings. These rings are thought of as the remainder of walls around buildings, The Express reported. According to one enthusiast, the structures are similar to ancient ruins found here on Earth, citing the structures on Mars are similar to those found in South Africa. Another enthusiast claim that the remnants are that of an ancient underground civilization.

NASA's official page neither confirm nor deny the existence of these structures and merely regarded the findings as the effects of volcanic processes on Mars. A full image was released that covers about 5 kilometers (3 miles) wide which would indicate the structures in question to be around 100 (330 feet) meters across.

It would be interesting to note that some of the structures form a pentagonal and hexagonal shapes as viewed from above. The finding was pointed out by one enthusiast, saying, that it was a great find since meteor impacts do not form pentagons or hexagons.

Meanwhile, back in October, alien enthusiasts claimed the existence of an ancient civilization was once present on Mars. The claim is also of a walled city ruin located on a peak on Mars. Another is that of an alleged spacecraft that crash landed in the Medusa Fossae formation.