Walk-in <a href="https://en.wikipedia.org/wiki/Camera_obscura" class="extiw" title="en:Camera obscura">Camera obscura</a> of the university at the <a href="https://en.wikipedia.org/wiki/Marburger_Schloss" class="extiw" title="en:Marburger Schloss">castle</a> in Marburg.
<a href="//commons.wikimedia.org/wiki/User:HeinrichStuerzl" title="User:HeinrichStuerzl">Heinrich Stürzl</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>