Swim around the world's longest underwater cave

Divers in Mexico have made an amazing discovery - the world's longest underwater cave.

They found that two underwater caverns in eastern Mexico were connected.

The cave is 216 miles long - which is around the same distance between London and Paris!

Inside the cave, they found pots and other relics left behind by the Mayan people, who lived there over a thousand years ago.

Come and have a swim around!

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