India, April 17 -- NASA has claimed that a huge hole on Mars could be a "portal" leading to an underground world of alien life. The space agency shared a photo of the opening in the Martian landscape as part of its Astronomy Picture of the Day series. The opening is 300-foot-wide. The hole, which spans about 328 feet, is located in the upper-right portion of a satellite photo.

"Actually, there are numerous holes pictured in this Swiss cheese-like landscape, with all-but-one of them showing a dusty, dark, Martian terrain beneath evaporating, light, carbon dioxide ice," NASA wrote. "The most unusual hole is on the upper right, spans about 100 meters, and seems to punch through to a lower level. Why this hole exists and why it is surrounded...