[clock_tower]

Wide-open spaces, even enclosed ones, can reduce the psychological burden of confinement quite a bit -- there's a variety of Russian strategic-missile submarine with a swimming pool, for example. This subject also comes up frequently in SF (science fiction, not San Francisco, which has the opposite problem); there was some discussion of it on the "Atomic Rocket" worldbuilding guide, IIRC.

[lambdadmitry]

I… I think the picture of that "pool" in your head is slightly wrong [1].

Tangential: the source [2] is pretty interesting.

[1]: http://pics.livejournal.com/igor113/pic/001e551p

[2]: http://igor113.livejournal.com/27205.html