One place I've always wanted to visit is the Colosseum in Rome. I finally got around to it this year, and it lived up to all my expectations. Completed in 80AD by the Emperor Titus, the Coloseum is made of concrete and stone. It is believed to have held between 50,000 to 80,000 spectators. According to our guide, the Colosseum operated a type of 'season ticket' approach, with each ticket holder knowing their entrance and place.
The outside of the Colosseum would have been painted a range of colours and each alcove contained a statue.
Underneath the 'stage', wild and exotic animals were often kept before being unleashed into the arena. Props, such as palm trees could also be hoisted into the arena using pulleys and trap doors. Our guide told us the days events often started with the animals being displayed.Then criminals were executed - sometimes using the animals, or being made to fight each other, before the day's final attraction, the Gladiators.
Note the holes in the concrete/stone - pillaged during the Middle Ages for the iron contained within.
No other way to put it - simply magnificent!