Beginning in 1922, archaeologist Charles Leonard Woolley, co-sponsored by the University of Pennsylvania and the British Museum, led a monumental excavation at Ur. Predating ancient Egypt and its famed pyramids by thousands of years, this southern Mesopotamian city-state possessed its own rich culture and architectural monuments, notably the ziggurat, a stepped structure topped by a temple. In extensive excavations undergone from 1927-1934, Woolley uncovered 16 royal tombs filled with precious royal artifacts, remains, and indications of human sacrifice.