Sea, sand, and sunset

Soothing as these seas are, they're also the biggest threat to the lowest-lying nation in the world. Some predictions warn that without preventive action, rising sea levels could completely swamp the Maldives by 2100. For decades, the islands' plight has led Maldivian leaders to advocate for climate action on the international stage—back in 2009, the national cabinet illustrated their point by convening underwater in scuba gear. The country has also become an innovator in the art of land reclamation: Hulhumalé, a 2-square-mile artificial island first settled in 2004, is already home to tens of thousands of people.