Nahm Tok Long Roo (น้ำตกลงรู - fig.) is a unique waterfall in Ubon Ratchathani, where the ‘water’ (nahm) ‘falls’ (tok) ‘down’ (long) from a round ‘cavity’ (roo), in the face of a gorge-like cliff. It is one of many attractions in Pha Taem National Park (fig.) and is also known as Nahm Tok Saeng Chan (น้ำตกแสงจันทร์), meaning ‘Moonlight or Moonshine Waterfall’, referring to the water that resembles beams of light coming from the disc-shaped cavity which is reminiscent of the moon.