The Colosseum is huge… Some 180+ feet high, built with 7 concentric
circles of walls, it had a roof made of poles, pulleys & fabric, and
an aqueduct system that provided 100 fountains of water to quench the
thirst of the 50,000 people who could be seated in it. Built around
80 A.D., it was built in only 8 years. Attendance was free for all
citizens who had their seating assignments guaranteed by a ticket of
inscriptions on a fragment of bone. The conduit systems could flush
water out or allow water to pour in. It truly was a colossal
structure so the nickname of "coloss-eum" was accurate. It took
humanity 1,900 years before it could build a larger one.