I'm never sure whether an image looks better by addressing the keystone distortion introduced by a camera or not. Sometimes I like the result; sometimes I'm not so sure.
It's the same way with tourists. If you want to show the 'street scene' you leave them in as they are an integral part of the scene. If, however, you are trying to see the architecture, particularly ancient archetecture, then they are a distraction and a PITA.
I had time on my hands and started playing. First, I started losing tourists and their shadows, next, the concrete bumpers were in the way, and then I thought, “If we wanted to see this as much as possible as it was 1,700 years ago, what else would need to be corrected”? However, there was no practical way to take down that ugly fence so there I was, halfway to my goal and very frustrated. To me, it feels like an unfinished painting.
Well, what is so fascinating about this 'Arch of Constantine'?
This huge triumphal arch (21 meters high), with three barrel-vaulted passageways, was erected to commemorate Constantine's victory over Maxentius at the Battle of Milvian Bridge in 312. It is just west of the Colosseum and dwarfs the nearby Arch of Titus. It incorporates recycled sculpture from earlier monuments, in part as some suggest, because creativity and technical skill had fallen off by this time period, but perhaps also because of a desire to associate Constantine with the "good emperors" Trajan, Hadrian, and Marcus Aurelius, whose monuments were cannibalized for sculpture. The faces of these emperors were recut to the features of Constantine.
For more information, please see:
http://en.wikipedia.org/wiki/Arch_of_Constantine