A UFO expert claimed one of the images captured by NASA’s Curiosity rover shows a doorway to an alien structure on Mars. According to the UFO expert, the doorway leads to an even bigger structure located underground.

The latest extraterrestrial-related claim about the Red Planet was made by Scott Waring of the UFO-centered blog ET Data Base. According to Waring, he came across the photo while browsing through GigaPan’s website, which was established as a collaborative project between the Carnegie Mellon University and NASA.

A cropped version of the image is also featured in an online gallery featuring the photos taken by the Curiosity rover.

Waring saw the alleged alien doorway on the large rock that appears to be standing upright along the side of a small hill featured in the photo. Waring noted that the structure surrounding the doorway was most likely made by hand using the raw materials available on Mars.

“The structure looks like it has been created from the materials on Mars, sort of a clay-like substance made by hand,” Waring stated in a blog post. “Instead of bricks, they used globs of clay. The entrance is huge on the back of the structure and can easily be seen since it has been painted white or coated white with some substance.”

According to the UFO expert, the structure was intentionally made to look like a rock in order to camouflage it.

Waring also noticed that the structure surrounding the doorway appears to have a tilted roof, which is very similar to the design of regular homes on Earth.

Based on the photo, Waring estimated that the structure could be about 6 to 7 feet long. The UFO expert also speculated that aliens may have built a larger structure underground beneath the doorway. The secret structure, which is most likely significantly larger than the one surrounding the doorway, could be hidden within the hill.

“The structure is about [6 to 7 feet] tall, but I believe that we only see about 5% or less, the other 95% will be below the ground to keep the home cool,” Waring stated.

SOL 981 This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 981 (2015-05-11 01:39:37 UTC) Photo: NASA/JPL-Caltech/MSSS