<a href="https://en.wikipedia.org/wiki/American_Civil_War" id="mwgw" rel="mw:WikiLink" title="American Civil War">American Civil War</a>: <a href="https://en.wikipedia.org/wiki/Battle_of_the_Crater" id="mwhA" rel="mw:WikiLink" title="Battle of the Crater">Battle of the Crater</a>: <a href="https://en.wikipedia.org/wiki/Union_(American_Civil_War)" id="mwhQ" rel="mw:WikiLink" title="Union (American Civil War)">Union</a> forces attempt to break <a href="https://en.wikipedia.org/wiki/Confederate_States_of_America" id="mwhg" rel="mw:WikiLink" title="Confederate States of America">Confederate</a> lines at <a href="https://en.wikipedia.org/wiki/Siege_of_Petersburg" id="mwhw" rel="mw:WikiLink" title="Siege of Petersburg">Petersburg, Virginia</a> by exploding a large bomb under their trenches.