Detail of a gate of the <a href="https://en.wikipedia.org/wiki/Eider_Barrage" class="extiw" title="en:Eider Barrage">Eider Barrage</a>
<a href="https://de.wikipedia.org/wiki/User:TeWeBs" class="extiw" title="de:User:TeWeBs">TeWeBs</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>