Paris - Geeky stuff to do or see?

In My Humble Opinion
21

The engineer might be interested in the Notre Dame Crypt, which shows the foundations of the old Roman settlement and some of the medieval foundations, as well as showing how the river bank has migrated over two millennia.

The bell towers are interesting, but it’s usually something like a two hour lineup to get in.

22

I can’t remember exactly where, I think it is somewhere in the Place de la Concorde. There is an original French Army Mobilization Order posted for World World I that you can still see.

24

Reported.