Ik-Kil Cenote, Mexico I have been here! It was beautiful! Swimmers float in the saphirre waters of the Ik-Kil cenote, near the Maya site of Chichén Itzá in Mexico's Yucatán Peninsula. Cenote means "natural well" in Spanish.
Travel: Austria's Green Lake in the Hochschwab Mountains is a hiking trail in the winter. The snow melts in early summer and creates a completely clear lake. The lake has a grassy bottom, complete with underwater trails, park benches, and bridges.