A cenote (English: /sɨˈnoʊtiː/ or /sɛˈnoʊteɪ/; Spanish: [seˈnote] or [θeˈnote]; plural: cenotes; from Yucatec Maya dzonot or ts'onot,[1] "well"[2]) is a deep natural pit, or sinkhole, characteristic of Mexico, resulting from the collapse of limestone bedrock that exposes groundwater underneath. Especially associated with the Yucatán Peninsula, and some nearby Caribbean islands, cenotes were sometimes used by the ancient Maya for sacrificial offerings. The term derives from a word used by the low-land Yucatec Maya, "Ts'onot" to refer to any location with accessible groundwater. Wikipedia link