Nearly every day, videos, photos and eyewitness accounts of UFOs pop up on the Internet.
Some are hoaxes. Some are quirks in the weather. Some sightings are never explained and forevermore remain UFOs.
The photo above, taken by Hannah McRoberts on Vancouver Island in British Columbia in 1981, is considered one of the most credible UFO pictures.
Still, never has there been widely accepted positive proof of an extraterrestrial spacecraft, though there are those who believe various government agencies around the world have conspired to hide the truth.
Now, however, if someone can prove otherwise, they will be $100,000 richer.
Filmmaker James Fox will make this announcement as part of the promotion for his upcoming movie The 701, inspired by the Air Force's two-decade UFO study, Project Blue Book.
The massive study into 12,618 UFO sightings, which ended in 1969, was able to explain away all but 701 of these sightings.
Fox, who previously directed Out of the Blue (2002) and I Know What I Saw (2009), will reveal the $100K challenge at the 22nd International UFO Congress (IUFOC), which begins Feb. 27, in Fountain Hills, Ariz.
"One of the aspects that sets our film apart is the producers' commitment to bringing forth never-before-seen evidence. As part of this effort, we're offering a $100,000 reward for the best proof that some UFOs are alien spacecraft," Fox told The Huffington Post exclusively.