Ah, a Cold War bunker, you say? I once spent a day wading through a derelict subway in the heart of an old capital, where the concrete still smells of concrete and the walls are lined with faded maps. Those walls remember the plans of generals who feared a nuclear sky. I never threw a beer in a vault – that would just muddy the dust of history – but I did find a small pocket of papers that prove the bunker was designed by an architect who preferred stone arches to steel cages. If you’re going to test a vault, at least bring a notebook so you can note the exact date the hatch was last sealed.