Switzerland is spending millions revamping its vast network of bunkers

I'm pretty sure my shelter is under the grocery store across the street from me but the annoying thing is that they don't tell you where your shelter is until you need it. The locations are somewhat secret. I know the location of another civil shelter farther away with the entrance under a highway because it has signs saying it's a shelter...

When I lived in Washington DC instead of shelters everyone had an assigned route for escaping the city by car.

We have an interesting app here in Switzerland - AlertSwiss. It uses your location to warn you about local dangers, like toxic air from a building fire, to landslides, to bad water warnings... you can also see all alerts in Switzerland on a map of the country. Currently there are a couple of landslides and some fires.

Interesting, in Finland we have a much more open approach. Shelters [are clearly marked](https://fi.wikipedia.org/wiki/V%C3%A4est%C3%B6nsuoja#/media/...) both on the door itself, and with signs leading to them.

[The large public ones](https://palvelukartta.hel.fi/fi/service/815) are even on published maps. There are lots more than these, though, as any residential building with enough residents need to have their own one built. This means that virtually all buildings have one, though usually it is only up to spec of the year when the building was built. I once lived in a building built in the early 1900s, and even it had a bombshelter in the basement, though very crude by todays standard.

I'm curious, what makes it crude vs. modern? e.g. Construction materials, floorplan, utility systems, amenities? Are the modern ones built stronger?

Just guessing here. But a shelter need to have mechanical ventilation, and a way to escape if the main door is blocked. So modern shelters usually have a plate at a wall, below ground, and when removed, lets dirt from the outside fall in and provides a way to leave the shelter. Such things may not have existed around 1900.