The mechanical switches and relays that route a phone call digit by digit were quite impressive to see, including manual switchboards where an operator would patch in your call with a physical banana plug. Here's a quick video summary:

Our great personal tour guide:

they used microwave links for point to point connections to other COs

an old AT&T video phone that worked over phone lines (with a slow bad picture due to line limitations)

check out the thousand+ amp switch with heavy copper

later semi electronic phone switches used boards like these, but they are impossible to fix or replace

it's fun to hand connect a thousand+ phone lines by hand in a conduit

before

after

Next, we went to the living computer museum, which also was quite good and gets credit for having many computers online you can interact with:

a 68k based Sun3, sweet (although it was slow)

the CDC 6600 was the first supercomputer before the Cray1

we had a Amstrad PC1512 at home

and an Amstrad CPC-464 too

we also had an Atari STF and later STE

Dongeon Master, I remember spending so many hours with this game

Both museums were quite interesting and worth the visit.