cenote

Mexico's Yucatan Peninsula has no rivers or lakes,however water fresh flows throughout its porous subsoil. Occasionally the soil gives way and opens a "grotto", or cave, usually with crystal clear fresh water, delightful for seimming, and sacred to the ancient Maya. Cenotes are connected by a labyrinth of underground rivers which are hardly explored and offer a new and challenging "sport", cave scuba diving. These fresh water fivers empty into the Caribbean and into the Gulf of Mexico.
"Cenote" has no translation to English, however some writers mistakenly use the word "sinkhole".