There are hundreds of extra-terrestrial conspiracy theories but the most common ones involve NASA most of the time. The premiere space agency has full access to classified and public data that explains why the agency is prone to be accused of a cover-up.

A recent report claims that NASA is covering up an alien city found on Mars.

  

According to a UFO hunter and blogger Scott Waring, NASA's Curiosity Rover photographed a section of what appears to be a Martian city with an apparent apartment building, but that the agency tried to prevent the public from viewing the said photograph. The image in question was published by NASA's Jet Propulsion Laboratory (JPL) in black and while showing a hill on the surface of Mars with the sky as its background, allegedly published in a small "thumbnail" size.

Alien chasers commend Waring with his latest "discovery" and evidence of alien life and civilization on Mars calling it a "historic breakthrough." Warring explained his findings in a post on the UFO Sightings Daily blog. Building with windows and doors perched on the hillside were seen according to Waring. UFO hunters said that the structures could be part of a large alien city or industrial buildings, factories or warehouses. What ignited the uproar was the fact the NASA only published the image as a thumbnail and not in a high-resolution format. This is part of NASA's attempt to cover up evidence of extraterrestrial life, according to UFO hunters.

"I found a photo on the NASA site, but the original is only 4kb in size," the veteran alien chaser said in a statement. "For those who don't understand digital sizes, this thing is so small that it could be an app icon on your cell phone. Fingernail size..." Waring added. The obviously small photo raised a red flag for conspiracy theorists. While Waring claims to enhance and enlarge the photo to reveal his "discovery."

The finding was posted on the blog on June 23. On the enhanced image, Waring asked if what he is seeing is building or "pixelated rocks?" The very small resolution of the photograph makes it really difficult to identify. But for Waring, this just proves that NASA is trying to get away with it by publishing really small image just to say that the agency is not hiding anything.

In 2015, a conspiracy theorist also accused NASA of hiding Alien underground bases on Mars, according to TechTimes. However, NASA is very careful when dealing with alien theories and prefers to speak about facts and data gathered by the agency's state-of-the-art equipment.

Earlier this year, a former NASA employee James Oberg, who dedicated his life to explaining every UFO sighting on Earth by comparing UFO sighting to NASA mission data, said he had enough experience with real spaceflight to conclude that what people claim as UFOs are nothing beyond the "norm."

Oberg added that people have a tendency to misinterpret events that are new to their perception and didn't occur in a normal setting.