This Saturday, June 2, is World UFO Day, the international holiday believers set aside to discuss the existence of space aliens and urge governments around the world to declassify UFO documents.
World UFO Day was created to honor U.S. pilot Kenneth Arnold's 1947 sighting of nine objects flying in tandem over Mount Rainer national park, according to WorldUFODay.com.
"Although most people are quick to associate UFOs with conspiracy theories or a cultural phenomenon it possible that one day one of these unidentified flying objects could prove an association with extraterrestrial life."
This year's UFO Day was chosen as a way to mark the anniversary of the UFO crash in Roswell, New Mexico and to encourage the U.S. government to declassify its documents.
When people look into the sky and can't identify what they see, it's technically referred to as an unidentified flying object, or UFO. Most strange sightings can be explained away as a bird, plane or weather balloon, but sometimes they can't, and that's when UFO aficionados start to speculate on the existence of space aliens.
There have been several unexplained UFO sightings over the years.
The most popular UFO incident occurred in 1947 outside a ranch in Roswell, New Mexico and alien invasion theories still focus on the event. It's this supposed alien crash that has become the focus of alien aficionado efforts to force the U.S. government to declassify documents.