Here is the mock up of the Colosseum.It size is 152mm x 127mm x 41mm (see the attached picture)

The Colosseum or Coliseum, also known as the Flavian Amphitheatre, is an oval amphitheatre in the centre of the city of Rome, Italy. Built of concrete and stone, it is the largest amphitheatre ever built and is considered one of the greatest works of architecture and engineering.