Hells Bells are hollow bell- or cone-shaped structures of carbonate that can reach lengths of 2 metres (6 ft 7 in). They are found underwater in El Zapote cenote in Quintana Roo, Mexico, on the Yucatan Peninsula; similar formations exist in other caves.
In a certain depth range, such structures cover the entire surface of the cave including submerged tree trunks and other Hells Bells, although they never touch each other.
The Hells Bells are speleothems that appear to have formed through incompletely understood complex interplays between water of the cave, microorganisms living in the cave, and the surface of the Hells Bells.
The name is a reference both to the shape of the structures and the lightless and toxic environment they are found in, and also to the song "Hells Bells" by AC/DC, and was proposed by cave divers.
Source
In a certain depth range, such structures cover the entire surface of the cave including submerged tree trunks and other Hells Bells, although they never touch each other.
The Hells Bells are speleothems that appear to have formed through incompletely understood complex interplays between water of the cave, microorganisms living in the cave, and the surface of the Hells Bells.
The name is a reference both to the shape of the structures and the lightless and toxic environment they are found in, and also to the song "Hells Bells" by AC/DC, and was proposed by cave divers.
Source