A photo taken by NASA’s robotic spacecraft accidentally revealed a massive alien city on Mars, according to a UFO expert. The expert claimed the image showed various clusters of building-like structures on the Red Planet’s surface.

Self-proclaimed UFO expert Scott Waring of ET Data Base came across the image of Mars after going through the photos provided by the Malin Space Science Systems (MSSS). Its website contains over 212,000 images that were all taken by NASA’s Mars Global Surveyor (MGS). This robotic spacecraft was launched in 1996 and spent a total of nine years in space observing Mars.

According to MSSS, the photo that Waring came across was taken by MGS in 1998. It was officially released by NASA in June 2000. Waring noted that the photo showed a complex portion of Mars’ surface. It showed a lot of landscape features such as a part of a crater, mountains and areas covered by shadows on the planet.

As Waring was analyzing the photo, he came across strange objects near the bottom of the image. Upon closer inspection, he noticed that many of the objects had geometric shapes, which clearly indicated that they were not natural features.

Waring then speculated that the objects could be buildings and structures used by an alien race on Mars. Given the number of the buildings he spotted as well as their distances from one another, Waring assumed the structures were part of an alien city on the Red Planet.

Aside from the structures, Waring also spotted holes on the surface of Mars. Since they didn’t have rims like craters, Waring theorized that the holes might actually be tunnels that led to an underground base or even a new network of cities underneath Mars’ surface.

Over the past couple of days, Waring has been sharing various UFO and alien sightings on Mars using photos provided by NASA. In a previous blog post, Waring said he saw different alien artifacts on the Red Planet. Many of these objects looked like brick walls, which Waring said were part of a massive temple that was built and used by an ancient alien civilization on Mars.

An image of Mars' Nili Fossae region taken by NASA's Mars Reconnaissance Orbiter. NASA/Christopher Kremer/Brown University