What is a coral reef??? Coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates called coral. The coral species that build reefs are known as hermatypic, or "hard," corals because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies. Other species of corals that are not involved in reef building are known as soft corals. There are hundreds of different species of coral, they have a dazzling array of shapes and colors, from round, folded brain corals (named for their resemblance to a human brain) to tall, elegant sea whips and sea fans that look like intricate, vibrantly colored trees or plants. Corals are found all over the world's oceans, from the Aleutian Islands off the coast of Alaska to the warm tropical waters of the Caribbean Sea. The biggest coral reefs are found in the clear, shallow waters of the tropics and subtropics. The largest of these coral reef systems, the Great Barrier Reef in Australia, is more than 2,400 kilometers. With the Thomas More tour, your will navigate through the canals and mangroves of the lagoon to reach the Caribbean at Punta Nizuc, the southern tip of the Island of Cancun. Here you'll go snorkeling at two different reefs and you'll have 45 minutes in each site to admire the beauty of the underwater world, book now right here: CORAL 
