The pool features underwater caves and a suspended, transparent, underwater tunnel for guests to walk through Credit: Caters News Agency. Emanuele said: "Y-40 is the only pool so deep with thermal ...

As if Dubai wasn’t filled with enough record-breaking attractions, the United Arab Emirates metropolis is now home to the world’s deepest pool, complete with an underwater city, caves and more.

A large sea cave with an underwater tunnel that runs from the pool, through the cliff to Canada’s Georgian Bay, The Grotto is known for the brilliant blue color of its waters. Divers have two ...

Although it’s not entirely underwater, part of this stunning cave includes an underwater pool that is perfect for swimming and diving. The cave is famous for its sheer size, with an opening that ...

This massive underwater sinkhole off the coast ... Grotto Azzurra was the private natural pool of the Roman Emperor Tiberius. The water cave is about 190 ft long and 82 ft wide.