When in Rome, visit the Colosseum. It’s a no-brainer to stop at the iconic amphitheater when traveling across Italy, but the nearly 2,000 year old structure is anything but overrated. Considered one of the greatest Roman works of engineering, the stadium not only hosted gladiatorial fights but dramas and battle re-enactments as well. The amphitheater also served as what is likely the oldest recycling project of all time. Throughout the millennia following the Colosseum’s heyday, the structure was re-purposed as a church, a medieval apartment complex, a burial ground, and even a castle. Now, of course, it mainly serves as a tourist destination and a backdrop for high profile concerts.