Fire in the Ballroom at the Royal Castle in Warsaw on September 17, 1939 after the severe bombing by the Germans.
unknown, scanned by <a href="//commons.wikimedia.org/w/index.php?title=User:Polaco77&amp;action=edit&amp;redlink=1" class="new" title="User:Polaco77 (page does not exist)">Polaco77</a>
1939-09-17
<ul><li>Lileyko Jerzy, Vademecum Zamku Warszawskiego, Warszawa, 1980. <a href="//commons.wikimedia.org/wiki/Special:BookSources/8322318189" title="Special:BookSources/8322318189">ISBN 8322318189</a></li>
<li><cite class="book" style="font-style:normal">Wiesław Głębocki; Karol Mórawski (1985)      <i> Kultura Walcząca 1939-1945</i>, <a href="https://en.wikipedia.org/wiki/en:Warsaw" class="extiw" title="w:en:Warsaw"><span title="capital and largest city of Poland">Warsaw</span></a>:  Wydawnictwo Interpress, pp. p.161  <small><a href="//commons.wikimedia.org/wiki/Special:BookSources/83-02-00773-0" title="Special:BookSources/83-02-00773-0">ISBN 83-02-00773-0</a></small></cite></li></ul>