Colosseum is of course the most famous land mark of Rome, which also means that’s where the longest lines are. To minimize waiting time, get there at the time of opening or during weekdays. Luckily lines do move pretty fast, and we only had to wait for 30min.
The interiors of the Colosseum are worth seeing and luckily at least when we were there (in the morning) it wasn’t too crowded inside. To be able to picture Colosseum in its old glory, I recommend getting yourself a guide book with details on the interesting history of performances and cruelty that took place in this huge amphitheatre able to host upto 40 00 spectators.