The Early Pleistocene sediments of Peninj, west of Lake Natron (Tanzania), contain a wealth of archaeological and paleontological sites formed during the emergence of the genus Homo and the extinction of the last australopithecines. Peninj has preserved tantalizing evidence that hominids, living in an open savanna, were acquiring animal resources through predation. Evidence also suggests that hominids repeatedly visited points on the landscape to conduct specific and distinct activities, such as butchering or tool manufacture. The lithic assemblage reveals complex planning in stone tool production and use, and the oldest evidence of woodworking. The results of the research described here constitute a major contribution to the study of human evolution and to reconstructing the behavior of early Homo erectus .