Kazem Dashi rock formation in Lake Urmia, Iran

Turning the tide

This beautiful lake in north-west Iran has had a rough couple of decades. Until around 1995, Lake Urmia was one of the top-ten largest saltwater lakes on Earth, and the centre of a thriving resort scene. Then drought, rising temperatures, water overuse and the building of a causeway across the lake reduced it to less than 10% of its size by the 2010s.

Now this salty lake (currently eight times saltier than the ocean) may be ready for a comeback. Over the last decade, multinational efforts to restore Lake Urmia have improved irrigation systems, reduced water usage and diverted water from other sources. So, for the last few years, these salt flats have slowly given ground to rising waters. It's still not quite a lake-half-full situation, but the upward trends have revived hopes that Lake Urmia's glory days will return.