The Civil War in the United States began in 1861, after decades of smouldering tensions between northern and southern states over slavery, states’ rights and westward expansion. The election of Abraham Lincoln in 1860 was the catalyst which caused seven southern states to secede and form the Confederate States of America; four more states soon joined them. The Civil War ended in the Confederate's surrender in 1865. The conflict was the costliest and deadliest war ever fought on American soil, with some 650,000 soldiers killed - nearly as many American soldiers as died in all the other wars in which this country has fought combined.
Teenaged soldiers -- both black and white -- of the Union Army.
General Lafayette's Headquarters, 1862
Bodies on the battlefield at Antietam, Maryland in September 1862.
Lincoln stands on the battlefield at Antietam, Maryland with Allan Pinkerton (the famed military intelligence operative who essentially invented the Secret Service, left) and Major General John A. McClernand (right) on October 3, 1862.
The USS Cairo on the Mississippi River in 1862.
Artillery at Yorktown, Virginia, 1862.
Entrenched along the west bank of the Rappahannock River at Fredericksburg, Virginia, these Union soldiers were about to take part in the pivotal Battle of Chancellorsville, beginning on April 30, 1863.
Confederate President Jefferson Davis.
U.S. President Abraham Lincoln.
The CSS Atlanta on the James River after Union forces had captured the ironclad Confederate ship in June 1863.
African-Americans collect the bones of soldiers killed in battle at Cold Harbor, Virginia, June 1864.
Partially titled "A harvest of death," this photo depicts just a few of the fallen soldiers at Gettysburg, Pennsylvania following the historic battle there in July 1863.
Three Confederate soldiers who were captured at Gettysburg, summer 1863.
Abraham Lincoln (indicated by red arrow) arrives at the dedication of the Soldiers' National Cemetery in Gettysburg, Pennsylvania on November 19, 1863, not long before delivering his Gettysburg Address.
Crewmembers of the USS Wissahickon standing by the ship's gun, 1863.
Union General Phil Sheridan.
Confederate dead at the Battle of Spotsylvania in Virginia, May 1864.
On June 18, 1864, a cannon shot took both arms of Alfred Stratton. He was just 19 years old. Overall, one in 13 Civil War soldiers became amputees.
Union soldiers from Company D, U.S. Engineer Battalion, pose during the siege in August 1864 in Petersburg, Virginia.
U.S. General Ulysses S. Grant in City Point, Virginia, August 1964.
Union soldier Francis E. Brownell, wearing a Zouave uniform, with a bayoneted musket. The Medal of Honor recipient has a black crape tied to his left arm in mourning for Col. E. E. Ellsworth.
U.S. General Ulysses S. Grant (center) and his staff pose in the summer of 1864 in City Point, Virginia.
Union officers and enlisted men stand around a 13-inch mortar, the "Dictator," on the platform of a flatbed railroad car in October, 1864 near Petersburg, Virginia.
Union General William T. Sherman sits on a horse at Federal Fort No. 7 September-November, 1864 in Atlanta, Georgia.
The Ponder House stands shell-damaged in Atlanta, Georgia, September-November 1864.
African-American Union troops at Dutch Gap, Virginia in November 1864.
Union soldiers sit by the guns of a captured fort in 1864 in Atlanta, Georgia.
Union Colonel E. Olcott.
Soldiers sit in trenches near Petersburg, Virginia, 1864.
A Union wagon train enters Petersburg, Virginia in April, 1865.
The ruins of the Confederate capital of Richmond, Virginia in April 1865.
The ruins of Haxalls (or Gallego) Mills in Richmond, Virginia, April 1865.
Ruins stand in front of the Confederate Capitol, circa 1865 in Richmond, Virginia.
Confederate Major Gihl.
The body of a dead Confederate soldier lies in a trench at Fort Mahone on April 3, 1865 in Petersburg, Virginia.
The ruins of the State Arsenal and Richmond-Petersburg Railroad Bridge are seen in 1865 in Richmond, Virginia.
Soldiers wait outside the court house in Appomattox, Virginia as the higher-ups work out the official terms of surrender in April 1865.
Two Union soldiers in Union captain's uniform and lieutenant's uniform, holding foot officers' swords, wearing frock coats, over-the-shoulder belt for sword attachment, and red sashes.
Taken sometime in 1884 or 1885, Jefferson Davis's family is pictured here in Beauvoir, Mississippi.
Wilmer McLean and his family sit on the porch of his house, where Confederate General Robert E. Lee signed the terms of surrender to Union General Ulysses S. Grant on April 9, 1865 in Appomattox Court House, Virginia.
The funeral procession for U.S. President Abraham Lincoln slowly moves down Pennsylvania Avenue in Washington, D.C. on April 19, 1865, five days after he was shot by Confederate sympathizer John Wilkes Booth and ten days after the Confederate surrender at Appomattox Court House, Virginia effectively ended the war.
Body of young Confederate and grave of Michigan soldier at Antietam, 1862