The Blue Cave or Modra Špilja in the small island of Bisevo, Croatia is one of the most extraordinary caves in the world.
For the most part, it’s unlike your usual cave that’s damp, dark, and brown-colored. As you might have guessed, Bisevo’s Cave is blue, but not because of some abnormality in the rock’s mineral content or some blue organism covering the cavern walls. For all you know, it would be dark, damp, and brown-colored all the same, if not for this hole at the bottom which allows sunlight to filter in through the waters.
The effect is an enchanting blue glow coming from the pool that illuminates the entire cave with a shimmer. The cave is most dazzling from 11AM to noon on a sunny day, when the sun is at its best.
Nonetheless, the Blue Cave isn’t as popular as other amazing caves because of its remoteness. To get to the glowing grotto, you must ride a ferry boat from Croatia to the island of Vis, where you could catch a bus or rent a motorbike to the tiny fishing village Komiza. From there, you could hire a boat to the island of Bisevo, and then get a smaller raft that could fit in the tiny 1.5 by 2.5-meter entrance of the cave.
But swimming in a glowing pool is sure worth the trip, though.