The World’s Biggest Underwater Cave

Researchers and professional divers have discovered that two caves—known as Sac Actun and Dos Ojos—off the coast of the Yucatan peninsula are actually connected by a long tunnel, making it the largest underwater cave known to us above-water creatures. The two caves measure 263km and 83km each, but now it’s known there is a 347km (216 mile) passage, meaning that Dos Ojos no longer exists, rather it’s now part of the solo cave: Sac Actun. Perhaps even more exciting, the researchers found artifacts from the first settlements in Mexico, plus the remains of now-extinct animals. Read more at Quartz.