14-16 years ago our band (not active anymore) was having 3 gigs at Russia and we spend one week there. During our stay in town with naval base, we get to visit some old training submarine. There was newer subs at the harbor too, but we were not allowed the get even close of them (nasty looking guards with guns)
But anyway we get to visit that older training sub, but it was tied to harbor and they didn't take us anywhere from there.
Too bad that at the time I was more interested in guitars and chicks, and not so much in subs
By the way. One gig was at some warship (most interesting place I have played)
Sailors at the warship were very kind and hospitality was excellent all the time.