Hidden among brilliant blue bodies of water around the world are mysterious and seemingly endless blue holes. These submerged sinkholes have captivated thrill-seeking divers and curious marine biologists for decades. Tourists, locals, and professionals flock to the sites with wonder of what new marine world they will discover so deep underwater. Many civilizations have passed down tall tales of mythical creatures lurking at the bottom of a blue hole.

Blue holes are dark patches of blue that are accessible by sea vehicle. These sinkholes gradually find their places in the middle of large bodies of water and become cavernous as the water shapes the rocks. Various teams have journeyed deep inside blue holes with advanced forms of technology to discover species of crustaceans like shrimp and bacteria that can survive in such dark conditions with a lack of oxygen.

If you feel drawn to the depths of the ocean inside a blue hole, a few have become notorious travel attractions. As soon as your face plunges into the sea, you are surrounded by coral, crustaceans, sea turtles, sharks, and a huge variety of fish. Beginners snorkel along the surface, while more experienced and dedicated divers explore further into the abyss. If you feel drawn to the bewildering environment inside a blue hole, consider this to be your newest travel bucket list.

Dragon Blue Hole in the South China Sea

If you are looking for the deepest underwater sinkhole in the world, this is your next travel destination. The Dragon Blue Hole in China is over 300 meters deep. Locals have passed down tales through generations of the “eye” of the South China Sea since the 16th century.  Most notable is the story from a famous Chinese novel, “Journey to the West,” chronicling the Monkey King’s possession of a golden weapon originating in the underwater world governed by a dragon king. The Dragon Blue Hole lacks oxygen in 66% of its depth, and the only lifeforms existing beneath 200 meters are extremophiles that can survive in hostile conditions. Closer to the surface is a marine world of over 20 species of fish. The Dragon Blue Hole is not as accessible to tourists as others, but it is a fascinating spot for researchers and divers with big imaginations.

Dean’s Blue Hole in Long Island, Bahamas

Before the Dragon Blue Hole of China was discovered to be 300 meters deep, Dean’s Blue Hole in the Bahamas, at 202 meters deep, was considered to be the most profound. Dean’s Blue Hole is a dreamy destination for tourists, with a crystal clear lagoon and pristine white sand beach on one side and vegetation on the other. Snorkelers and divers find themselves encompassed by naturally formed rock walls and an abundance of sea life, from fish to turtles and stingrays. If you are a beginning diver or snorkeler, Dean’s Blue Hole is a good option due to its calm waters and easier accessibility. Although a popular blue hole site, the island is quaint, peaceful, and defended from mass tourism. The locale is reachable by small plane from Nassau followed by a car ride or boat tour.

Great Blue Hole in Belize

The stunning Great Blue Hole off of Lighthouse Reef is filled with the clear waters of the Caribbean Sea. The cavernous site lies among the famous Belize Barrier Reef, which is the biggest barrier reef north of the equator. The Great Blue Hole is home to a variety of sharks, turtles, fish, and coral. Stalactites and stalagmites are astounding features of the hole that spans 318 meters wide and 124 meters deep. Renowned oceanographer Jacques Cousteau boated to the Great Blue Hole in 1971 and labeled it as one of the best places to dive in the world. You can book tours by boat from San Pedro in Ambergris Caye that take you to the Great Blue Hole for snorkeling and diving experiences.

Blue Hole in Dahab, Egypt

Expert divers are attracted to the thrill of the Dahab Blue Hole, known as one of the most treacherous underwater sinkholes in the world. Its environment confuses some divers into traveling deeper and experiencing nitrogen narcosis, which results in altered consciousness and other health hazards. The dive site is located in the Red Sea and drops 120 meters below the water’s surface. Inside the Blue Hole of Dahab, divers wedge themselves through rock formations and are amazed by the eye-catching openings and a tunnel known as the “Arch” that rises over 50 meters high. The Dahab Blue Hole houses many species of colorful fish.

Blue Hole in Gozo, Malta

Malta is an archipelago located south of Italy in the Mediterranean Sea. Hidden inside the city of Gozo in Malta is a 15-meter-deep blue hole surrounded by limestone rock formations. Divers are attracted to the lesser depth of the Gozo Blue Hole, the archway almost halfway down, and its remarkable cave towards the bottom. The water is cold but crystalline in the Fall months. You can drive to the locale and snorkel without a tour, but look out for urchins on the rocks and swelling water. Blue Hole divers are also able to book guided tours.