Scuba diving in Yucatan Cenotes can be recommended. Cenotes are natural sinkholes found throughout Mexico that form when the roof of an underground cavern collapses.
Anhumas Abyss is a cave 23km from the city of Bonito Mato Grosso do Sul, Brazil. During some days of the year the sun passes through the small opening of the cave, producing a beam of light that illuminates the cave for a few hours.
Wow. Two worlds apart: underwater, and beneath the starlit night