Tat Yuang, as some signs spell it, is impressive, with its twin torrents falling about 40m and flowing into lush jungle. It's hugely popular with day trippers from Pakse and tour buses from Thailand, so getting there early or lingering late is a good idea. An easy set of steps leads down to the main viewing area and to a little bridge that takes you to the top of the waterfall.
A fun stairway leads through the forest to other viewpoints, where you'll be hit with spray from the falls in the rainy season, and a path leads all the way to the bottom. Swimming at the top is fine year-round, but don't try to swim at the bottom in the rainy season.
It is 10km to the access road from Paksong, then 1.2km from the highway to the park. A guesthouse near the entrance should be open in 2017.