This one time on an episode of Survivorman, Kalahari iirc, I watched Les Stroud use a hole in the dirt and a clear plastic tarp covering it to act as a solar still. The condensation from his pee in said hole ran off to a collection container as pure H20 once evaporated.

I just remember thinking to myself "Bear Grylls drinking his own pee is such a philistine, here is an actual pro using science to remove all the water from that pee instead first." Genuine moment of awe personally.