There are more ‘Blue Holes’ in The Bahamas than anywhere else in the world, as well as the deepest Blue Hole on earth. From the surface, they can appear mythical, and in fact, Blue Holes feature in a number of Bahamian marine legends.

But these distinct circles of dark blue water surrounded by an ocean of brilliant cerulean blue are not portals to a mystical netherworld. They are the entrance to aquatic sinkholes and underwater caves.

Exploring Blue Holes is a highlight of any diving excursion, where you may discover magnificent geological features like stalagmites, sheer limestone walls and dazzling mineral formations that enhance the feeling of uncovering an underwater mystery and swimming back into prehistoric times.

Even if you’re not a certified diver, some Blue Holes in The Bahamas can be discovered by swimming, snorkeling, or even hiking.

Here are four of the best Bahamian islands to explore a Blue Hole:

1 The Island of Andros:

This island has more than 200 Blue Holes, and is something of a holy grail for divers, who come from all around the world to this island to get into a Blue Hole. Luckily for non-expert-divers, most of the Blue Holes situated offshore of Andros are also accessible. Two of the most popular activities are snorkelling the surface of a Blue Hole or hiking to the site of an inland hole. One of the best Blue Holes to check out in Andros is ”The Crater.” It sounds immense, but this small Blue Hole is well suited for both experienced and more novice divers. The walls of ”The Crater” are home to a thriving reef system, where fish, moray eels and rays make their way up and down the walls, and turtles are commonly seen floating along.

2 Long Island:

The bay west of Clarence Town on Long Island is home to Dean's Blue Hole, the deepest Blue Hole in the world. Dean’s Blue Hole plunges to a depth of 663 feet (202 meters) - maybe. No human has been able to reach its bottom, so this Blue Hole remains a fascinating mystery. That may sound intimidating, but, since it’s enclosed, the wind does not penetrate the diameter, making it an ideal dive or swim even for beginners. This blue Hole is also connected directly to the Atlantic through an inlet on one side and framed by cliffs and white sand beaches on the other, making it an equally marvellous sight from the surface.

3 Nassau, New Providence:

Another island in The Bahamas has one of the most unusual dive sites in the world. The Lost Blue Hole’s vast dimensions – a 100-foot diameter and depth of over 200 feet - attract scuba enthusiasts from all over the planet, and it is on many divers’ bucket lists. The sheltered walls of this extraordinary dive site shield it from external currents and waves, ensuring outstanding clarity. That also provides an ideal habitat for a wealth of marine species, including nurse sharks, reef sharks, angelfish, snappers, amberjacks, yellowtails, manta rays, moray eels and sea turtles.

4 Great Abaco Island:

Many travellers to The Bahamas know its northernmost island as a yachting and fishing paradise. But Abaco’s best-kept secret is that it has more than 100 Blue Holes and limestone caves right beneath the island. One of the easiest and most intriguing places on this island to explore is the 250-foot-plus deep Treasure Cay Blue Hole. Located in the middle of the Pine Forest in Treasure Cay, this geological phenomenon contains a mixture of salt water and fresh water, and due to its inland location it is not known to have any marine life. Visitors can fly from a tree swing and cannonball inside this extraordinary, inland Blue Hole.

If you’ve never heard of the Blue Holes of The Bahamas, and even if you’re not a scuba diver, now’s the time to add them to your island travel bucket list.