A picture from the inside of the famous Coliseum in Rome, Italy. This is an amazingly complex structure, with a maze of warrens underneath where the original stadium floor existed.
This largest of all the Roman coliseums was completed and opened to the public between
80 and 90 AD (88 AD I think?). The two story maze of passageways, complete with elevators
and raisable ramps, was added a few years later.