Street art (graffiti) by an unknown artist(s) at NSA listening station on Teufelsberg in Berlin Grunewald.
<a href="//commons.wikimedia.org/wiki/User:KK_nationsonline" title="User:KK nationsonline">KK nationsonline</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>