Plate tectonics and seafloor spreading revolutionized the big picture of how our planet works. Scientists were eager to explore the details of what was happening at the seafloorclose-up and first-hand. They wanted to confirm, for example, that hydrothermal vents actually existed. Starting with some tantalizing clues that resulted from research in the 1960s, a flurry of research cruises in the 1970s gave scientists the prize they soughtand something else that they never expected.;xNLx;;xNLx;Photo: Tubeworms, clams, and crabs at a hydrothermal vent site. (Image courtesy Timothy Shank, Woods Hole Oceanographic Institution)