by Heidelberg University, November 24, 2017 in ScienceDaily

In recent years, researchers have identified a small group of stalactites that appear to have calcified underwater instead of in a dry cave. The Hells Bells in the El Zapote cave near Puerto Morelos on the Yucatán Peninsula are just such formations. Scientists have recently investigated how these bell-shaped, meter-long formations developed, assisted by bacteria and algae.