In 1864, during the Siege of Petersburg by the Union Army of the Potomac, a mine made of of gunpowder was set off approximately under Maj. Gen. Ambrose E. Burnside's IX Corps sector. The explosion blew a gap in the Confederate defenses of Petersburg, Virginia, creating a crater long, wide, and at least deep. The combat was accordingly known as the Battle of the Crater. From this propitious beginning, everything deteriorated rapidly for the Union attackers. Unit after unit charged into and around the crater, where soldiers milled in confusion. The Confederates quickly recovered and launched several counterattacks led by Brig. Gen. William Mahone. The breach was sealed off, and Union forces were repulsed with severe casualties. The horror of this engagement was portrayed in the Charles Frazier novel, and subsequent Anthony Minghella movie, "Cold Mountain".