12.Dean's Blue Hole

We know that that dark blue area doesn’t look that interesting. But there’s a reason Dean’s Blue Hole is one of the most popular venues for freediving in the world. (In fact, an annual freediving competition is held here.) Below the surface is a vast cavern considerably wider than the top; it stretches roughly 330 feet wide. The blue hole is below water level and descends 203 meters, or approximately 666 feet deep, making it the second-deepest known sinkhole under the sea.

From Dean’s Blue Hole, we next travel up to The Bahamas to visit the Great Blue Hole…