abstract
apartheid
auschwitz
background
barb
barbed
barbwire
barrier
black
border
boundary
camp
chain
concentration
crime
danger
day
electric
europe
fence
freedom
gate
genocide
germany
guard
history
holocaust
intrusion
iron
isolated
jail
memorial
metal
military
nazism
poland
prison
protection
razor
safety
security
shape
sharp
sky
steel
symbol
trespassing
war
white
wire