The word “cenote” comes from the Mayan "dz’onot", which means “cavern with water”.
Cenotes are deep reservoirs of water that are fed by the filtration of rain and by the currents of underground rivers.
Their formation dates back millions of years, in the last Ice Age. The area of the Yucatan Peninsula was covered by the sea, which descended and left the exposed coral barrier that gave rise to a limestone floor.
The limestone is very porous and allows the filtration of rainwater, which results in the numerous tunnels and underground caverns forming the underground rivers. When the limestone is worn away, it collapses creating the cenotes.
Cenotes were sacred for the ancient Maya and served as their primary source of water. The Maya had a strong connection to the cenotes and considered them the entrance to the underworld.
Estimated 6,000 cenotes are found on the Yucatan peninsula, whereas less than half of them are studied and registered.
Cenotes, like people, have different ages. However, you will never find two similar cenotes even if they are the same age!