Spent many years in Boston, and never even knew this Mapparium thing existed. Thanks for posting - I really hope I have a chance to check it out sometime in the future.
I only knew about it because my brother-in-law did film production for the Christian Scientists, and knew all about it, so everyone in his family knew of it.
LOL, he would sometimes mutter with a grin “Mary Baker Eddy! Mary Baker Eddy!” like it was a prayer mantra! (He wasn’t a Christian Scientist, but got enjoyment out of poking them a bit...)
I am from Boston, and I have walked by that place several times when I was younger. My work is right down the street. I dunno, maybe I will check it out, especially as I have long been fascinated by maps.
Maybe I will.