Pyongyang is known for having the deepest underground subway stations in the world. At a depth of over 110m (360 ft), the stations also serve as bomb shelters. As with many other architectural and design facets throughout North Korea, the subway station designs are reminiscent of Soviet-designed stations. Although I haven't been to Moscow, several of the subway stations there are also quite extravagantly decorated.
Once people realize that travel in North Korea is never without minders chaperoning you around, they tend to follow up with questions asking if you can meet or talk to regular North Koreans. Well, the answer is both yes and no.
Riding the Pyongyang Metro is an excellent opportunity to interact with regular North Koreans. The caveat is, you may have to overcome a bit of a language barrier, but nowadays more and more people are learning [British] English, and I even had a guy come up and start speaking in English to me! When I first visited North Korea in 2008, kids were ducking behind walls and windows when they saw the tour bus driving by. What a world of difference a few years has made!