Alfred Wegener (1880-1930), German geophysicist and proposer of the theory of continental drift. Impressed by the matching coastlines of South America and Africa, Wegener suggested in 1912 that there had once been a single supercontinent (which he called Pangaea) that had fragmented and drifted apart into the continents we know today. Although he supported his argument with sound evidence, he was at a loss to explain the underlying mechanism and the theory was discounted during his lifetime. Later discoveries proved him right and led to the new discipline of plate tectonics, now a major tenet of geology. Wegener died while crossing an ice sheet during an expedition to Greenland.