Clapp (left) and his friend Andy Castro, who was his divemaster on the 2023 PADI Club trip to Belize. Diving the Blue Hole in ...

This Land of Enchantment swimming hole is renowned by scuba divers and Route 66 road trippers for its cool temperatures and stunningly clear water.

Like other sea-holes or "vertical caves," the Great Blue Hole in Belize's Lighthouse Reef actually formed on dry land, during a past ice age when the sea level was a lot lower than it is today ...