6The Colosseum, Italy

The Colosseum, or Flavian Amphitheatre, is an enduring symbol of ancient Rome’s architectural prowess and grandeur. Completed in 80 CE under Emperor Titus, this massive amphitheater could hold up to 50,000 spectators. It was used for gladiatorial contests, public spectacles, and mock sea battles. The Colosseum’s innovative design includes a complex system of vaults and arches, as well as a retractable awning system to shield spectators from the sun. Despite centuries of natural disasters and human activity, the Colosseum remains an iconic landmark and a testament to Roman engineering and entertainment.