This “vertical cave” is a paradise for divers and photographers—and it might explain the fall of Mayan civilization.
When we see sinkholes on the news, they’re usually disastrous and frightening, swallowing up Australian campgrounds and Florida used car lots with abandon. But let’s not forget the fun, chill kind of sinkhole: the underwater kind! The Great Blue Hole off of Belize, for example, is not just the most obviously named place in the world (tied for #1 with Australia’s Great Sandy Desert). It’s also a bucket list destination for just about every scuba diver on the planet.
Before it was blue, it was still great, and a hole.
Like other sea-holes or “vertical caves,” the Great Blue Hole in Belize’s Lighthouse Reef actually formed on dry land, during a past ice age when the sea level was a lot lower than it is today. The ground collapsed due to water dissolving limestone (your garden-variety eating-a-Florida-backhoe type of sinkhole) forming a big circular pit that was eventually submerged by the rising Caribbean. The striking contrast between the shallow, coral edge and the seemingly bottomless center gives these blue holes their colorful name.
Take a journey to the “center” of the Earth.
Scuba buffs flock to the Great Blue Hole for its crystalline waters, abundance of sharks and coral, and stalactite-filled caves, proof that it formed on dry land. About fifty feet below the surface, divers see the water shimmer as they pass the “halocline”—the invisible line that divides that salty top of the hole from its freshwater depths.