Built in Eight Years

The Colosseum was finished in roughly eight years (70-80 AD) with no power tools, no cranes, and no steel. That is faster than many modern stadiums.

The structure used about 100,000 cubic meters of travertine stone, held together by iron clamps rather than mortar. Centuries later, looters pried those clamps out for their metal, leaving the pockmarked holes that scar the stone today. A monument to imperial power, raised by the people that power had conquered.