Tag des offenen Denkmals
... that during Tag des offenen Denkmals, Germany's largest annual cultural event, thousands of historic monuments are opened for free?
... that during <b id="mwvw"><a href="./Tag_des_offenen_Denkmals" id="mwwA" rel="mw:WikiLink" title="Tag des offenen Denkmals">Tag des offenen Denkmals</a></b>, Germany's largest annual cultural event, thousands of historic monuments are opened for free?