The famous discovery our oldest ancestor began as a jigsaw puzzle. The fossil of what we recognize today as Australopithecus afarensis, or Lucy, had to be pieced together in fragments. Only 40% of her skeleton was found intact, but for a hominid from 3.2 million years ago, the number of bones unearthed in 1974 in Ethiopia was still remarkable. After her discovery, researchers took the fragments of Lucy's skull and reconstructed what they believed she would have looked like, an assemblage that became startlingly humanoid. With long arms and short legs, she stood about 3 ft. 7 in. tall and weighed about 60 lb. The finding suggested that bipedal locomotion in our earliest ancestors preceded the development of a larger brain.