"Swimmin' Hole" - Adams Falls, Ricketts Glen State Park, Pennsylvania - Such a beautiful place!!
Blue Lake Cave, Brazil
Slovenian Caves - the Grand Canyon of the underground.
Fingal's Cave, Scotland
This is a hand carved cave in Abiquiu, NM near Ghost Ranch.
Harrison's Cave,Barbados: - PixoHub
Luray Caverns large column, Virginia
The Glory Hole in Ozark National Forest, Arkansas