The Colosseum is roughly elliptical in shape, with its long axis, oriented WSW-ENE, which measures 188 metres and the short one 156. The building stands on a base of two steps; above it there are three floors of arcades and a fourth storey without arches but with small rectangular windows. There were eighty arches on every floor, divided by pillars with a half column. The four arches on the axes of the building were the main entrances, and were probably decorated with a little porch and a statue. The other 76 arches were numbered for an easier access to the seats. Only 31 arches of the outer ring, from number XXIII to LIV, have remained intact. All around the rims of the first three floors there were circular promenades that could accommodate most of the public in case of rain. The arches are 4.20 metres (13’9") wide and 7.05 m (23’1") high on the ground floor, while on the upper floors they are only 6.45 m (21’2") high. Including the cornices between the floors and the attic, the overall height of the building is 48,5 m.