I saw a program on The History Channel abotu this guy who build a bomb shelter that has like 3 or 4 levels below his house (probably bigger than the damn house itself ed: ).
The first level is a trick so if people found out and tried to get in they would think that the first level is all their is, but really there were secret doors from teh first level to the other ones.

He also made a system for dropping teargas and stuff into the first room, to chase people out in the event of WWIII.
I'll bet that guy was pissed off when the USSR fell apart, all those resources wasted.