Watercolor "Old Castle" (Benrath). Artist Kaspar Wolf.
<a href="https://en.wikipedia.org/wiki/Caspar_Wolf" class="extiw" title="w:Caspar Wolf">w:Caspar Wolf</a>
Schloß Benrath, <a href="//commons.wikimedia.org/wiki/Special:BookSources/3-7701-52158" title="Special:BookSources/3-7701-52158">ISBN 3-7701-52158</a>