Lake Anasta is a body of water located somewhere in North Africa. At one point, it wasn't a lake; just dry land, as located on its seabed is a temple.
Lake Anasta Pipeline
Running from the lake, across the desert, is a pipeline, which Brains uses a navigational guide to find Lake Anasta.
Brains, Tin-Tin and Professor Blakely set up camp beside Lake Anasta, before making their first dive on the temple.