The Colosseum in Rome covers an area of about 6 acres (2.4 hectares) and measures 620 feet (189 meters) long and 513 feet (156 meters) wide, with a height of 157 feet (48 meters). It was completed in AD 80 and could accommodate approximately 50,000 to 80,000 spectators. The Colosseum is an architectural marvel featuring 80 entrances and intricate vaulting and is considered one of the greatest works of Roman engineering. It welcomes around 7 million visitors each year.