Draining of Lake Velinus, artwork published in Specula Physico-Mathematico-Historica (1696), an encyclopedia of science by the German monk and author Johann Zahn (1641-1707). The text is in Latin. This massive lake, which filled the Rieti Valley in southern Umbria, Italy, was drained by the Romans in 271 BC, leaving behind Lake Piediluco (top right). They dug a canal that led to the formation of the Marmore waterfall (upper right). The river shown here is the River Nar. The area was also famous for its geothermal properties, with sacrifices being made in a volcanic area (bottom).