Especially in Rome with the Vatican. And churches galore. With my (somewhat) catholic wife, we have quite a bit of fun observing the ancient history of religion in Rome(and elsewhere). We both love it, for different reasons.

I'm amazed by the ancient churches, their architecture and construction, and the ancient builders. I was engrossed in Lucca where building-recycling was a common practice, even a millennia ago.

Some of the ancient buildings there are complete patchwork quilt of parts from bygone eras. In an ancient church listening to an Opera(the sound-fantastic), I was sitting next to a massive stone column. It was a mismatch to the others(typical), and had a fluted section added to the top, as it was too short for it's new function.

And then building went so slowly back in those days, the best laid building plans, often didn't keep up with civilization. The buildings are history, heaped on history.

And there they are, these ancient buildings, perfect records of a thousand(s) years ago, still standing. I compare that to a few 2x4's sheathed with OSB and wrapped in TYPAR- all full of rot in 20 years,... and I get depressed.