Why does the roman coliseum have a crack in it?

Answer 1

It was finished in AD 80 so it is very old and many things have happened to it. During the middle ages it was used as a fort and from the 15th century it was used as a source for building materials for Rome's palaces. People took the iron fittings and used them as well. By the 1700's it was a ruin and since 1750 it has been dedicated to Christian martyrs killed there. Conservation began in the 19th century and is ongoing.

Answer 2

because of the weather