In the Art Gallery of Palazzo Pamphilj, on the fourth floor, there is Terrazza Borromini, framing one of the most striking views of the famous Piazza Navona. The building that houses the Borromini Terrace is the seventeenth-century 'Collegio Innocenziano', which stands in an area of great archaeological interest. The area of Piazza Navona, in Roman times was occupied by the Stadium built by Emperor Domitian in 86 AD, an imposing elliptical travertine building that hosted athletic competitions for almost four centuries. After the 5th century, the Stadium gradually fell into disrepair, but its arena, known as the Campus Agonis (Field of Games), continued to host jousts, festivals and shows of all kinds.