What was the key to the support of the Colosseum in Rome?

Answer 1

Concrete and the vaulted arches were keys to the support of the Colosseum. It was built with a mixture of concrete and stone. The Romans were in the middle of developing concrete and were unsure of its strength and durability, so they used stone as well. Roman concrete proved to be very strong and long lasting and it is mainly due to this that it has survived. Moreover, unlike stone, it cannot be quarried to be used as building material elsewhere, which is the main reason why so many Roman buildings are in ruin. The great load-bearing strength of the vaulted arch was also very important in supporting the Colosseum.