The reef is made up of many different types of coral, from branching staghorn coral to round brain coral that looks exactly like the surface of a brain. Hundreds of fish in every colour - parrotfish, angelfish, sergeant majors - dart in and out of the coral.
Glass-bottom boats have a section of their hull made from thick, clear glass or perspex. When the boat moves slowly over the reef, passengers can lie on benches and peer straight down at the underwater world below them, like looking through a window into the sea.
After the reef tour, most boats stop at a spot called the Nylon Pool - a shallow, turquoise sandbar sitting in the open sea. The water there is only knee-deep and brilliantly clear, and you can wade around as if you are standing in a swimming pool miles from shore.
Coral reefs are very important ecosystems - they provide a home for around a quarter of all ocean fish. Buccoo Reef is protected, which means fishing and anchoring on the reef are not allowed, helping the coral stay healthy for future generations to enjoy.