The Surprising Truth About The World's Deepest Sinkhole

If you hear the word "sinkhole," the first thing you might think of is a subreddit about jazz reinventions of classic Star Wars leitmotifs, Facebook debates about politics, or perhaps the most obvious timesink of all: cats failing to make jumps to the tops of refrigerators. 

In reality, a "sinkhole" is, according to the United States Geological Survey, an environmental feature that traps water and does not allow it to drain. At least, the water soaks into the substrate on the underside of the sinkhole before draining to a river, stream, or the ocean. Sinkholes tend to form in areas where rock dissolves when it comes into contact with water, called "karst terrain," such as salt beds and limestone. Water can either burrow itself into pockets that resemble caverns, or just make a big hole like a well. Sinkholes tend to get attention when their surface collapses and creates an irregular ring on land that just creepily drops off into nothing. When they collapse, it happens with minimal warning, and if they collapse in an urban center, they can swallow entire roads and buildings.

Some sinkholes, such as those in Guatemala City, caved in after a week of strange sounds and left the landscape pockmarked with holes, per Momtastic. Others, such as those in Bimmah, Oman, are older and have been converted, in this case, into a swim park. One sinkhole, however, is so huge and stunning that it looks like a portal into another world, hewn into a mountainside.