The Colliseum looks like it was in a war zone, with bullet pock marks everywhere.
Not so. The Romans used iron pins
to anchor the rock blocks in place. Because iron was a valuable commodity, once
the Roman Empire collapsed,
opportunists chipped away enough of each block's corner to harvest the iron pins.
Earthquakes in 847 AD and 1231 AD
caused enough shifting of the unpinned blocks to collapse part of the Colliseum.
Had the pins not been removed, the
Colliseum would mostly still be standing tall.