It's amazing how well the Romans perfected infrastructure, isn't it? The Pantheon is something I'd like to see some day, though I'm not sure I'd be willing to go to Rome to see it. That section of wall does, indeed, look to be fairly well preserved for something so old.

When I lived in Spain, I was surprised to see how well some of the sections of the Roman road were preserved. There were areas that looked to be almost perfectly intact.