Deep-sea volcanic ridges, formed by the collisions of tectonic plates, create underwater hot springs in an otherwise frigid environment. These hydrothermal vents belch warm towers of elements that draw clusters of animal life, such as tube worms. Scientists have been intrigued by the vents, and the types of creatures that live around them, for half a century. There, animals develop symbiotic relationships with bacteria that use chemical reactions to produce sugars necessary for life beyond the reach of sunlight. Now, the study of deep-sea fauna has led to the discovery of an unexpected ecosystem where life thrives in the most unlikely of places.