Lake Salda's blinding white beaches are not sand at all — they are the crumbled remains of rock that microbes are still building today. In the shallows, cyanobacteria and algae strip magnesium from the water and lay it down as hydromagnesite, growing lumpy, cauliflower-shaped mounds that Turks call the White Islands; waves grind those mounds into pale, pebble-like grains. Over the white shoals the water throws back a tropical turquoise, and Turkey calls the lake its own Maldives. The magnesium comes from the hills: Salda fills a closed tectonic basin with no outlet, ringed by serpentinite whose slow weathering leaves the water alkaline and extraordinarily rich in magnesium. Hardly anywhere else on Earth is this kind of rock still forming, which is why NASA in 2021 named Salda the closest known match on Earth to the minerals ringing Jezero Crater on Mars — the dried-up lakebed where the Perseverance rover is sealing rock cores in the hope of a future return to Earth.
Wade out and the colour climbs the whole scale: milky blue over the pale floor, then turquoise, then a green so dark it reads as ink where the bottom falls away toward 196 metres. Late summer gives the most, because as the lake draws down in the dry months the white shoals surface and the beaches widen. The White Islands themselves, though, can no longer be touched. Visitors trampled the living mounds for years and scooped the white paste onto their skin as a face mask, so since October 2021 the beach and the water there have both been closed, and you look from behind a wooden barrier. Salda is a nature park inside a Special Environmental Protection Area, and you may swim only at the marked public beaches, where black pine forest runs down to the shore.