Coliseum Rome
One of the most recognizable structures in the world, the Coliseum was opened in 80 A.D. Originally used a venue for gladiator contests and wild beast hunts, the Coliseum later became the site where the first Christians were tortured and killed by animals. Afterwards it was neglected, and began to deteriorate rapidly. Eventually Pope Benedetto XIV's edict consecrated it to the memory of the Christian martyrs, putting an end to its slow destruction. In 1808 it was restored by Pope Pious VII.

The greatest amphitheater of the Roman world, The Coliseum consisted of four levels with a capacity of some 50,000 people, who, in case of bad weather, were sheltered by a system of coverage consisting of striped cloth, maneuvered by one hundred sailors.

Today you can get a pretty good sense of the Colosseum just by walking around the outside, but going inside will give you a better idea of the seating areas, the structures beneath the arena floor, and the overall enormity of the building.