abandoned
army
barbed
barbed wire
barbwire
border
boundary
building
camp
colony
complex
crime
criminal
derelict
empty
escape
fence
forbidden
forgotten
freedom
gaol
guard
gulag
history
imprisonment
jail
lookout
military
no people
nobody
outdoor
prison
protection
punishment
repression
russia
russian
security
sky
soviet
tower
wall
watch
watchtower
wire