Researchers have found the world's deepest blue hole in the Latin American country of Mexico.
They have reached 1,380 feet or 420 meters below sea level, but it is not the end of the hole.
The “deepest known blue hole”, Taam Ja’ Blue Hole (TJBH), is located in Chetumal Bay off the Yucatan Peninsula.
Its depth can be compared to the height of Trump Tower in Chicago.
Blue holes are water-filled vertical caverns, found in coastal regions where the bedrock is made of soluble material, such as limestone, marble, or gypsum.
Blue holes typically contain tidally influenced water of fresh, marine, or mixed chemistry.
Well-known examples are the Dragon Hole in the South China Sea and, the Great Blue Hole and Dean's Blue Hole in the Caribbean.
The Dahab Blue Hole in Egypt and the Great Blue Hole in Belize are other good examples.