Blue holes are huge deep holes that exist on land or in the ocean. Which are the seven largest blue holes in the world?

The Great Blue Hole

In the waters about 100 kilometers away from Belize City, Honduras, there is a purely natural ring-shaped deep sea cave surrounded by atolls. , was discovered in 1971. Now because of the birth of the Great Blue Hole, it has become an international tourist attraction, especially for these diving enthusiasts.

Because the water level here reaches nearly 137 meters, the scenery in the water is very beautiful and has not suffered any environmental pollution. Experts are also constantly studying this purely natural garden landscape and feel that it is blue. The establishment of the cave was mainly due to the ice age of more than 2 million years, which caused the sea level to continue to drop. Finally, the mutual corrosion of water and the sea caused the formation of many karst cavities in the calcareous area. It was not until the climate warmed that the sea surface submerged the karst. Hollow, a strange natural scene forms in the ocean! Dean's Blue Hole

Dean's Blue Hole is an underwater maze located in a harbor in Clarence, Long Island, Bahamas. It is 1,500 kilometers long and contains tunnels formed during the Ice Age. and caves, one of the most dangerous new realms in the deep world. This deep-sea cave located in the Bahamas is the deepest blue hole in the world, and is therefore known as Dean's Blue Hole. Its depth reaches 202 meters, which is about twice as deep as other blue holes. It is the choice of professional diving enthusiasts. In 2010, William Trubridge set a Guinness World Record by diving to a water level of 101 meters without using oxygen bottles or other professional diving equipment.

However, this also brought others to follow suit. In 2013, there was a diver who just wanted to test William Trubridge’s diving test scores, but something unexpected happened during the process. He unfortunately died later. Although this blue hole attracts many explorers every year, people who live nearby are afraid of the blue hole. This group of people believe that the cave was excavated by "devils" and is aimed at It is extremely dangerous for people to break into the blue hole. Hadab Blue Hole, India

The Hadab Blue Hole is located in the Red Sea. There is an arc-shaped passage at the deepest point near the Hadab Blue Hole. Many patient divers braved the wind and rain to reach it to express the His skills are outstanding. Because of many tragic events, the Blue Hole in the Red Sea is even called the "Tomb of Divers" by the outside world. The Blue Grotto of Capri, Italy

The Blue Grotto of Capri is known as one of the seven wonders of the world. The entrance of the Blue Cave is at the bottom of the cliff. The entrance is not large and can only be entered by boat. Because of the special structure of the cave entrance, on the one hand, sunlight can enter the cave from the entrance, and on the other hand, it is reflected from the water inside the cave. Therefore, the sea water in the cave is crystal blue and unpredictable, and even the rock formations in the cave have become It is dark blue, hence the name "Blue Hole". Saipan Blue Hole

Saipan Blue Hole is located in the northeast of Saipan. It is the most famous and difficult snorkeling place in Saipan. Potential customers can often be seen here training for diving. The cause of blue holes is actually similar to underground rivers on land.

Almost all deep-sea blue holes are karst cavities. During the Ice Age hundreds of years ago, a lot of water formed glaciers, which lowered the sea level. The basalt layers were exposed on the ground and slowly grew into large and medium-sized cavities. After the Ice Age was completed, the glaciers melted and the sea flooded such cavities again, forming Today's Blue Hole. At present, some blue holes have been developed and turned into tourist attractions. For example, the famous Great Blue Hole in Belize is a holy place for diving enthusiasts.

In the eyes of experts, deep-sea blue holes are a rare scientific research treasure. Blue holes rarely interact with the external aquifer, but most caves are rich in nutrients. Specific groups of organisms usually live in blue holes, and there is no shortage of animal living fossils and microorganisms left over from prehistoric times.