Dome

Close view of the obelisk base; The same cardinals also controlled a council for the reclamation of the Acqua Vergine, to which della Porta was appointed (1568) in place of Nanni di Baccio Bigio. In addition to works related to the channelling of water, completed in 1570 when water reached the basin of the Trevi Fountain, his responsibilities included the construction of public fountains, and he designed those in Piazza Navona (from 1574), Piazza Colonna (from 1575), Piazza del Pantheon (begun 1575; remodelled 1711 by Filippo Barigioni) and Piazza S Marco (from 1588). [The fountain is topped by an Egyptian obelisk.] Source: Grove Art Online; http://www.groveart.com/ (accessed 2/8/2008)