A groundbreaking expedition into Belize’s Great Blue Hole uncovers a jaw-dropping discovery. As the submarine descends into ...

The Dragon Hole is about 990 feet deep, surpassing the third-deepest blue hole, Dean’s Blue Hole, by over 300 feet. The Taam Ja’ Blue Hole is more than twice as deep as Dean’s Blue Hole.

The blue water spring is about 13 feet in diameter and 1 foot below the rim, USGS said. The water in the pool was measured at ...

It's a limestone cave, to be exact. The Great Blue Hole contains stalactites and stalagmites below the surface, some 40 feet in length. And as with any good cave, more mysteries lie within.

“Blue holes” are underwater sinkholes that open below the seabed. The hole, dubbed “Green Banana,” opens up at 155 feet below sea level. The bottom of the hole is at a depth of about 425 feet.