In the middle of the bushy evergreen forest of Umphang Wildlife Sanctuary,Tak Province, two creeks are flowing down from Doi Ma Muang Sam Muean and joining at the same place on the high cliff which resembles the heart shape. It`s recognized as one of the most beautiful and highest waterfall of Thailand. The only name of this waterfall is `Pitugro`.Petro Lo Su is the name that people call it later.