Famous with the backpacker set since the mid-1980s, the monthly Full Moon Party held on the island of Koh Phangan in Thailand is the stuff of legend. Begun by an impromptu group of less than 50 revelers, this gathering has grown to include more than 20,000 people on the evening of every full moon like clockwork twelve months out of the year. Is it a tourist trap of epic proportions? Yes. Is it amazing and worth checking out nonetheless? You bet.joestump via Flickr.