The Tamerza waterfall is modest in height, but it has the same startling effect as all water in this landscape. A spring-fed stream cuts through pale rock and drops into a shaded pool, with palms and reeds crowding the edges. After kilometres of bare desert road, the sound of falling water feels almost theatrical.
The pool and gorge are a popular stop on mountain-oasis tours, so expect company when buses arrive from Tozeur. It is still worth the stop. The gorge walls show layers of old sedimentary rock, and the short walk from the road gives a quick, vivid sense of how these oases survive: not by broad rivers, but by small springs finding weak points in the stone.