There's a Lake That Turns Animals to Stone

The secret to this Tanzanian lake's bizarre preservative power lies in the unique geology of the Great (Review) Rift Valley. The nearby volcano, Ol Doinyo Lengai, is the world's only active volcano that erupts natrocarbonatite lava, which is exceptionally rich in sodium carbonate. This mineral washes down into the shallow lake, creating a caustic, alkaline soup with a pH that can rival household ammonia. This intensely chemical-rich water is what prevents the normal process of decay for any creature that succumbs to its environment.

When birds and other animals perish in these waters, the high concentration of sodium carbonate and other salts acts as a fantastic natural preservative. This process is remarkably similar to the one used by ancient Egyptians, who harvested a substance called natron—a mixture of sodium carbonate and sodium bicarbonate—from dry lake beds to dehydrate and preserve bodies for the afterlife. In Lake Natron, the water (Review) essentially mummifies the remains, and as it evaporates under the hot sun, it leaves behind a high concentration of salt that encrusts the creatures, calcifying them and locking them in stone-like poses.

Despite its deadly nature for most species, the lake is paradoxically a vital breeding ground for millions of lesser flamingos. Their tough, scaly legs offer protection from the caustic water, and they feed on the salt-loving algae that give the lake its surreal, blood-red hue. For these specialized birds, the inhospitable lake provides a perfect sanctuary, keeping their eggs and chicks safe from predators that cannot withstand the toxic (Review) environment.