In 1958, it was decided that a nuclear shelter to protect the seniors of the Canadian Government would be built. In addition, several other such shelters would be built around the country to aid in dealing with nuclear emergency and rebuilding. Construction of CFS Carp, the largest facility, began in 1959 in an abandoned gravel pit that was found to have an underground water spring.
CFS Carp is a 4-story complex capable of housing 500 people. Hot-bunking was used to cut down the number of required beds. As one shift worked, the other shift slept.
Massive blast doors, air filters, and enough reinforced concrete and earth to withstand a near direct nuclear detonation were designed to keep the inhabitants safe.
In 1994, the Canadian Government decided to close the facility, deeming it obsolete, and sold it to the township of West Carlton. In 1998, the doors were reopened as a museum as it continues to serve today.
I don't think it's completely possible to understand a nuclear shelter until you've actually been in one. Even then, you have the knowledge that when the tour is complete, you'll be ascending to the surface, the fresh air, and the world you know. It is difficult to comprehend going into one, hearing the massive steel door close and seal behind you, and knowing that the world into which you will eventually emerge is entirely different.
So, this is a museum, and you are guided through a tour. Two things I personally don't care for. Despite that, however, I was still quite fascinated by this place. It was a peak into a potentially horrific time that thankfully never happened.
While the tour was fairly informative, there were many areas that were not covered. It would have been nice to have time to wander independently on more than the top-most level.
All of that aside, I highly recommend visiting here if you find yourself in the Ottawa area.