>Gone is your childhood home, gone your school, gone the people who defined it. it's nice to have something around that seemingly lasts forever like the earth and sky. Makes us feel home, when home is long lost to time.
What makes monuments like Notre Dame or the pyramids special is that they DO imbue this sense of continuity. Everything else in our lives comes and goes, but a few things we as a society come together collectively to say "This is special and worth preserving." There is a special feeling of connection one gets from that sense of unity across time. These are the things that give us a sense of shared history and a shared future destiny. And it has the effect of simultaneously making you feel individually small and insignificant, but also important and part of something grand.
The first time I visited Paris I remember one of my most dominant thoughts was that nothing like this will ever be built again. There is so much in the art and architecture that, by modern standards, would be deemed wasteful and extravagant and a suboptimal use of resources. We don't value aesthetics in the same way. So when these things go, they're gone forever. Even if remade they will only ever be an imitation of a way of thinking and a way of life that has gone extinct.
They won't even serve to remind us of those old ways because the gestalt you get from layering generations of use and the peculiar artifacts of the material culture that created it will be gone. That's why people mourn. It's not just about the building, but the fact that the building anchors them to a sense of tradition and continuity.
And it's not the first time these things happened. It was mentioned that before it was a Christian church it was a temple to Jupiter in that location. Removing the old pagan monuments was a conscious effort to FORCE just such a break from the past. To say the old pagan ways are over and to sever any sense of continuity with that old culture and their old Gods. I'm sure it was just as troubling or traumatic then too.
We still have some collected myths and stories from the Romans and the Norse and so on, but a lot of these were written by Christian converts who were sad that the stories they heard on their grandparents' knees were going to disappear. They may have converted, but they felt like this was something important that needed to be preserved.