The Battle of Gettysburg, the largest battle ever fought in the Western hemisphere, is often called the turning point of the Civil War. The battle was a narrow victory for the Union and could have been a Confederate victory if it were not for a series of critical events. One such episode involved the 20th Maine Infantry. Organized in the Maine Volunteer Militia in August 1862, the 20th Maine mustered into Federal service several weeks later. Assigned to the Army of the Potomac, the regiment fought in the Antietam, Fredericksburg, and Chancellorsville campaigns. At Gettysburg, the 20th was commanded by Colonel Joshua L. Chamberlain, a former professor at Maine's Bowdoin College. After marching all day and night to reach Gettysburg, the regiment was ordered late in the afternoon of July 2 to occupy critical terrain between two hills, Big and Little Round Top. Chamberlain was ordered to hold this position on the extreme left flank of the Union line at all costs; if outflanked by the Confederates, the entire Union position would be in jeopardy. It was not long before the 15th and 47th Alabama Regiments attacked. The 20th Maine held off six attacks by the determined Alabama men, but Colonel Chamberlain knew that his regiment, low on ammunition, could not withstand a seventh. He therefore ordered a counterattack with fixed bayonets, and the 20th charged down the slopes of Little Round Top into the startled Confederates and broke their attack. The 20th Maine took 400 prisoners and stopped the Confederates threat to the Union flank. The crucial role these Maine militiamen played in the Union victory at Gettysburg exemplifies the military qualities of leadership, initiative, unit cohesion and gallantry. Joshua Chamberlain was awarded the Medal of Honor for his actions of July 2, 1863. At Appomattox Courthouse almost two years later, it was Brevet Major General Chamberlain, chosen to accept the Confederate surrender, who ordered Union troops to present arms to their former enemy as a mark of respect. After the war Chamberlain was elected Governor of Maine, and completed his military career as a major general in the Maine National Guard. The heritage of the 20th Maine is carried on today by the 133d Engineer Battalion, Maine Army National Guard.