Sinkholes are natural holes in the Earth's surface caused by a ground depression and the resulting collapse of the weakened surface. A sea sinkhole is similar to a sinkhole on land, except it is located in the sea and filled with fresh water. Off the coast of the beautiful country of Belize, close to Belize City, there is a giant sea sinkhole called the Blue Hole, which has attracted visitors from around the world.


The Blue Hole lies near the center of Lighthouse Reef, located approximately 60 miles from Belize City. The hole has a depth of over 450 feet and a diameter that reaches almost 1,000 feet. The barrier reefs scattered around the Blue Hole can be found approximately half a mile offshore from the city of San Pedro. This hole was not made by man, nor was it constructed overnight. It has taken thousands of years to become the wonder that can be seen today. Several ice ages needed to have occurred in order for the Blue Hole to achieve its current size. During an ice age, the sea level is lower, allowing these holes to be formed through erosion by rain and weathering, after which they are submerged by the sea again. The ice ages that contributed to the making of this particular hole occurred 153,000; 66,000; 60,000; and 15,000 years ago.

The discovery and subsequent fame of the Blue Hole occurred in 1972, when the famous scientist, researcher, and naval officer Jacques Cousteau visited the area. In 1996, the Blue Hole was named a UNESCO World Heritage Site, along with the Belize Barrier Reef Reserve System, and it was also declared as a National Monument in 1999. Jacques Cousteau said that the Blue Hole is one of the top ten scuba diving locations in the world.

Exploring the Blue Hole

Scuba diving is a common way to visit the Blue Hole. Divers from around the world come to the Blue Hole to admire the beauty of this submarine sinkhole. There are several dive sites scattered throughout the Blue Hole, allowing divers to experience the interesting geographical formations showcased here. The contrast of the bright turquoise water that surrounds the darker blue of the sinkhole is not only stunning but also mesmerizing. As divers begin their descent down into the Blue Hole, they will notice interesting and often multi-coloured rock formations. Snorkeling is also a good way to view the Blue Hole, offering a less intense experience of observing its inhabitants and formations. It should be noted that for safety reasons, the diving instructors at the Blue Hole only allow intermediate and advanced divers to take the plunge into the abyss. If diving and snorkeling doesn’t suit you, there are also aerial tours with various local airlines, allowing visitors to admire the Blue Hole from a distance.

Life Forms

The life forms that can be found in and around the Blue Hole are both extraordinary and abundant. These include colourful reed fish and several different species of shark, such as the reef shark, nurse shark, bull shark, hammerhead, and blacktip shark.