Phi ta khon is a type of masked procession celebrated on the first day of a three-day buddhist merit-making holyday known in thai as boon pra wate the annual festival takes place in may june or july at a small town of dan sai in the northeastern province of loei participants of the festival dress up like ghosts and monsters wearing huge masks made carved coconut-tree trunks topped with a wicker-work sticky-rice steamer the procession is marked by a lot of music and dancing the precise ongit of the phi ta khon is unclear however it can be traced back to a traditional buddhist folklore in the buddha's next to last life he was the beloved prince