Barbed wire perimeter fencing near by the entrance to the German death camp Auschwitz I in Poland. Note the electrical insulators on the concrete fence-posts. The barbed wire was electrified with lethal voltages, to kill any escapers. Additionally, the top of the fencing is deliberately designed to slope inwards thereby making it more difficult to climb over, even without electrical current running through it. The view is taken from the outside, looking into the camp. In addition to the 2 electrified fences there is a third "dead-line" fence just beyond, visible in the middle distance. Any prisoner stepping over the low third fence would immediately be shot dead without warning by perimeter guards.
<a href="https://pl.wikipedia.org/wiki/Wikipedysta:Pimke" class="extiw" title="pl:Wikipedysta:Pimke">Pimke</a>
CC BY 2.5 pl
<span class="int-own-work" lang="en">Own work</span>