Battle of Hel
...that during the Battle of Hel, one of the longest battles in the 1939 Polish September Campaign, Polish forces temporarily separated the peninsula from the mainland, forming an island?
...that during the <b id="mwIQ"><a href="./Battle_of_Hel" id="mwIg" rel="mw:WikiLink" title="Battle of Hel">Battle of Hel</a></b>, one of the longest battles in the 1939 <a class="mw-redirect" href="./Polish_September_Campaign" id="mwIw" rel="mw:WikiLink" title="Polish September Campaign">Polish September Campaign</a>, <a href="./Polish_Armed_Forces" id="mwJA" rel="mw:WikiLink" title="Polish Armed Forces">Polish forces</a> temporarily separated the <a href="./Peninsula" id="mwJQ" rel="mw:WikiLink" title="Peninsula">peninsula</a> from the mainland, forming an island?