A year doesn't seem to go by without these earth-shattering and shocking proof coming to light that aliens and UFO exist. So, hold on to your tin foil hats, because this one will give you chills.

After discovering the secret doorways on Moon and Mars, alien hunters have again found a black secret doorway to the underground alien world on Mercury planet.

In a video posted on Youtube, alien hunters claimed to discover the unexplained shadow on Mercury caused by a large structure.

UFOlogist Scott C Waring together with the seekers has identified a rectangular object to the planet that looks like a doorway used by aliens and UFOs as a secret passage to enter the underground world.

In a NASA photo of the Mercury surface, viewers can see a black rectangular structure which the conspiracy theorists believe an entrance that extraterrestrial beings used to travel to the underground world.

Scott C Waring of UFO Sightings Daily described it as a doorway that stretched more than three miles. For alien hunters, the secret passage was a shadow cast by a giant rectangular monolith.

"I was looking over some Mercury photos and found this unusual black doorway. It is long and rectangle in shape with four almost perfect right-angled corners. Unless meteor cubes are pummelling planets, this seems to be made by ancient aliens," UFO Hunter Scott C. Waring said.

The 19-minute video which was posted online has been viewed for more than 260,000 times and has already gone viral. The crater left of center is approximately 26 miles (42 kilometers) in diameter.

According to an alien hunter Tyner Glockner, the angle of the sun that casts a shadow on the northern walls of the craters proves that the black rectangle is a shadow cast made by a standing structure.

Scott Waring believes those aliens and UFO live in the underworld which is why humans failed to catch them live. This secret doorway is their passage towards it. Many viewers are still convinced that the video is an unequivocal proof of alien's existence.