Colosseum made from material travertine
Physical description
Exterior
Unlike Roman theatres that were built into hillsides, the Colosseum is an entirely free-standing structure. It derives its basic exterior and interior architecture from that of two theatres back to back. It is elliptical in plan and is 189 meters (615 ft / 640 Roman feet) long, and 156 meters (510 ft / 528 Roman feet) wide, with a base area of 24,000 square metres (6 acres). The height of the outer wall is 48 meters (157 ft / 165 Roman feet). The perimeter originally measured 545 meters (1,788 ft / 1,835 Roman feet). The central arena is an ellipse 87 m (287 ft) long and 55 m (180 ft) wide, surrounded by a wall 5 m (15 ft) high, above which rose tiers of seating.
The outer wall is estimated to have required over 100,000 cubic metres (3.5 million cubic feet) of travertine stone which were set without mortar; they were held together by 300 tons of iron clamps. However, it has suffered extensive damage over the centuries, with large segments having collapsed following earthquakes. The north side of the perimeter wall is still standing; the distinctive triangular brick wedges at each end are modern additions, having been constructed in the early 19th century to shore up the wall. The remainder of the present-day exterior of the Colosseum is in fact the original interior wall.
constructed from material fabricated from material composed of material formed from material manufactured from material