Koyashskoe lake in Kerch, (Crimea). Located in the Opukske Reserve, Lake Koyashske is considered to be the saltiest in Crimea – a liter of its water contains 350 grams of salt. The lake’s main highlight is its changing-colour properties that depend on the season(when it’s hot, the water is pink-coloured). The unusual color of the lake is due to the microscopic algae living in the water. Another reason for the lake’s red color is the high population of brine shrimps that live there.
Just a pool, disguised as a pond, with a trampoline instead of a diving board.
I wrote a paper about these kinds of pools several years ago for a class when they were just prototypes. These pools have a natural filtration system that run based on the plants that are in the pool that give the water nutrients that allow it to not only be crystal clear, but you are also able to drink the water because it becomes so clean. And the best part is that once the initial filtration system is installed and calibrated, it maintains itself and eliminates the need for chlorine or constant maintenance like salt water pools.