Dome

General rear view of statue of Pollux and horse; The colossal pair of marble "Horse Tamers", often identified as Castor and Pollux, have stood since Antiquity near the site of the Baths of Constantine on the Quirinal Hill, Rome. (The Dioscuri or Dioskouroi refer to both of the twins Castor and Pollux). They are fourth-century Roman copies of Greek originals. They gave to the Quirinal its medieval name Monte Cavallo, which lingered into the nineteenth century. Between 1589 and 1591, Sixtus V had them restored and set on new pedestals flanking a fountain, another engineering triumph for Domenico Fontana. In 1783-1786 they were re-set at an angle, and an obelisk, which had recently been found at the Mausoleum of Augustus, was re-erected between them. (The present granite basin, which had served for watering cattle in the Roman Forum was set between them instead in 1818.) Source: Wikipedia; http://en.wikipedia.org/wiki/Main_Page (accessed 2/1/2008)