Colosseum, Rome

The most famous ancient architectural building in Rome is Colosseum (Colosseo). I am so impressed of Romans' intelligence, they used two half circles theatre to join a whole circle theatre, which formed the amphitheatre, Colosseum.

Did u noticed the underground inside of the colosseum? It was a hypogeum built for gladiatorial contests at that time. Basically it was for their entertainment, there were other shows such as animal hunts, famous battles or dramas. The building ceased to be used for entertainment in the early medieval era but it was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine. Fortunately they stopped anomal hunts since 523.

Here is a picture of colosseum in night view.

(Image credit: http://www.arielbravy.com/photoblog/index.php?showimage=8)