I suppose I was lucky in that I visited these places long before package holidays became popular, and no-one had a phobile moan with which to take selfies. There weren't so many crowds, and it was all generally calmer.

(Except the Palace of Versailles, which was so crammed with sightseers that one couldn't see anything much, just the back of the person squashed in front!)

If I'm visiting a church, mosque, cathedral, chapel etc I like to try and sit quietly somewhere and reflect for a time, and offer up a few silent prayers.
One can always buy postcards or guide books with good photos to keep.