A giant hole on Mars has scientists baffled and some UFO researchers are theorizing it could be the work of extraterrestrials.
In a video obtained by conspiracy theorist Youtube channel SecureTeam 10, a deep depression in the surface of Mars has astronomers questioning what it is.
Tyler Glockner, who runs SecureTeam 10, said the hole is estimated to be hundreds of feet across. The rocky terrain of Mars -- which like Earth, has polar ice caps -- does not account for what the depression is, Glockner added.
The images come courtesy of NASA's Mars reconassiance orbiter, which has been exploring the planet.
Below is the video in its entirety:
NASA has given several possibilities of what could have caused the hole, including meteorites, lava tubes, ancient floods and volcanoes. But conspiracy theorists have other ideas.
Glockner said the hole shows artificial characteristics, noting that it looks as if it has been hollowed out. Glockner added that the hole could also be an entrance of an underground civilization.
SecureTeam 10, which has nearly 900,000 YouTube subscribers, often runs conspiracy theory-based videos. The organization describes itself as the "source for reporting the best in new UFO sighting news, info on the space cover-up, and the strange activity happening on and off of our planet."