The construction of the Colosseum was very much a symbolic gesture to create a clear distinction between Vespasian and his predecessor, Nero.
The Vatican Museums is important historical artefacts and works of art in the world. Originally the site of the Vatican Museums was used for papal palaces.
The Colosseum, sometimes spelled "Coliseum", was built between 70 and 82 AD in the heart of Rome. It was called the Amphitheatrum Flavium or Flavian Amphitheater because it was built by the the Flavian emperors, Vespasian and Titus. Some say is was able to hold 87,000 spectators, but more likely it was around 50,000, still monumental for the time.
The Colosseum is one of the best Ancient Sites in Rome. The ticket line can be long. Read Tips for Buying Rome Colosseum Tickets for ways to avoid the long line.
There is an elevator in the Colosseum enabling those with limited ability to walk up stairs to enjoy the Colosseum.
Outside the Colosseum you'll find good photo ops with people dressed as Gladiators during peak times, but you'll have to pay them for posing. Of course there are a number of souvenir vendors, too.