Swim among millions of stingless jellyfish.
Hundreds of mantas feed in this tiny bay during the monsoon plankton blooms.
The largest reef in the northern hemisphere: nurse sharks and rays at Hol Chan, turtles and 500 species of fish.
Drift between the American and Eurasian tectonic plates in gin-clear glacial water.
Fringing reef in Western Australia where whale sharks cruise close to shore.
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