https://www.jocogov.org/facility/the-1950s-all-electric-hous...
Of course thus would be powered by nuclear energy.
However, the low voltage wiring is very neatly done, and it still functions perfectly. Since low voltage wiring is so small, it means a bank of nine switches can easily fit in a single gang box (in the form of a 9-position dial and a single switch). Also, some lights are controlled by as many as five switches, since it's so easy to daisy-chain another switch, and I love that I can shut off the detached garage lights from inside the house.
The main disadvantage is that it's difficult to add dimmers to lights, since the line voltage isn't in the switch box.
This relay-driven system just screams to be hooked up to a computer system to add "smart home" features, and I actually started doing that. I got a prototype working with a Raspberry Pi and some home-made circuit boards to the point where I could ask Siri to turn on any light in the house, but I'm no electrical engineer, and before long my boards started to fail.
I disconnected it completely a long time ago because it started to make the relays stick and all the switches in the house stop working. It's actually my parent's house, so I didn't want to make modifications to it or affect the current switches at all, just add a little smartness. I still want to get back to it when I get the chance.
The house was built in the mid-70s by a commercial electrician, and even the closet lights are connected to it. There are about 50 switches/relays in total. We've had to replace 3 or 4 of them in the last ten years, but that's all.
All the low-voltage wiring is out in the open. The relays are cylindrical and poke out of knockouts in the relay panel. The relays are of the latching type, so only require power to switch on/off. Three wires to each relay and switch: red/on, black/off, and white/common.
I don't know why, I just love them to bits.