This may look like something from an alien planet, but it’s actually Yuncheng Lake in China. It’s one of the country’s oldest salt-production sites. People have mined salt there for at least 4,000 years!
In the summer, huge algae blooms color the lake blue, green, and red. The colors are stunning, but unfortunately excess algae are a type of pollution that puts local wildlife at risk. The algae use up the oxygen in the water as they grow. This leaves less for fish and other plants and animals in the lake, causing them to die off.