Colosseum, Rome

The Colosseum is the world's largest ancient amphitheatre, completed in 80 AD under Emperor Titus. Capable of seating 80,000 spectators, it hosted gladiatorial contests for over 400 years and remains Rome's most recognizable symbol. At 48.5 meters tall. Its concrete structure used 100,000 cubic metres of travertine stone, weighing 300,000 tonnes. Today, 6 million visitors per year explore its ruins, paying €16 per ticket.