Bunkers may serve our needs, but there’s a lot to be said for the garden variety castle, situated on the high ground with a spiffy gate to bar any moaning shufflers. I spent the last two weeks in so many easily defended stone buildings. Edinburgh castle has never been taken by direct force in over half a millenium, only by stealth, trickery and siege. Since zombies suck at stealth and trickery, locations like Edinburgh Castle could prove the perfect outbreak retreats, assuming the siege problem could be addressed — that is, assuming defenders laid in enough food and supplies to wait out the apocalypse if the undead made provisioning impossible.
(In the real world, the above cannon is pretty useless for the average zombie outbreak. I just like the picture. Unfortunately, it’s hard as hell to shoot somebody in the head with a cannon ball.)