public baths, racecourses like the circus maximus, and the great amphitheater decreed by t emperor vespasian in 75 a.d. with its massive facade of superimposed arches, the colosseum seems to express in stone the grandiose dreams of all empire-builders. but it was a most functional building-- its gates numbered for ticket holders, its concentric vaulted corridors designed to funnel 50,000 spectators to their seats with maximum efficiency. built of stone, brick, and concrete, the colosseum's huge oval interior offered every roman an unobstructed view of the slaughter in the arena below-- arena being the latin word for the sand that covered the wooden floor and absorbed the blood. today the colosseum impresses us more as an amazing feat of architecture than as a work of art, though it strongly influenced the design of both renaissance palaces and modern sports arenas. this thr-dimensional scale model depicts rome in the fourth century, virtually at the end of its spectacular imperial building program. of all the great constructions throughout the empire, one stands above all others ashe crownin