07/06/2012 02:45 pm ET Updated Dec 06, 2017

Celebrate World UFO Day (WATCH)

On Monday we celebrated the 11th annual World UFO Day. World UFO Day both honors unexplained celestial phenomena as well calls for explanations of such phenomena. For those who honor this day, wondrous and eerie reverberations can still be felt from Roswell, and conspiracy theories and government cover-ups are parts of the norm. Even for those who are not theorists or UFO investigators, UFO's have captured our imaginations. From flying saucers to SETI; from Close Encounters of the Third Kind to Independence Day, Aliens and their crafts have caused all of us to ask what else is out there. So for this World UFO Day, watch a list of the top 10 UFO sightings of all-time, and ask yourself if we are really alone.

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