World's second-deepest blue hole found in Mexico: What is this undersea sinkhole and why is it so mysterious?
The second-deepest blue hole has been discovered off the coast of the Yucatan Peninsula in Mexico. The underwater cavern is about 900 feet deep. Blue holes are believed to be formed during the latter ice ages around 11,000 years ago and might have answers to life on other planets
Source: firstpost.com