Cave of the Sleeping Sharks
Just 30 minutes off the coast of Cancun near Isla Mujeres lies a popular diving destination called Cave of the Sleeping Sharks, which has baffled marine biologists everywhere. Sharks must constantly be in motion in order to breathe through their skins, but in this cave the sharks can use bubbles from underwater springs to breathe, allowing them to "sleep" completely still.
The Cave of the Sleeping Sharks was discovered in 1969 and lies about 60 feet (20 meters) underwater, formed by coral formations that allow divers to get close to the resting sharks. Nurse sharks are most commonly seen in the cave and although they are harmless it is still exhilarating to be able to swim so close to them.
The Cave of Sleeping Sharks is part of the Los Manchones reef outside of another popular area for diving enthusiasts, El Garrafón. This dive recommended for more experienced scuba divers as the cave can be reached between 65 and 100 feet (20 to 30 meters) underwater. There are many attractions nearby to observe local marine life, if swimming with sharks is too adventurous for your taste.