March 19, 2014
From In Syria: Three Years of War, one of 37 photos. This picture taken the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) shows residents of the besieged Palestinian camp of Yarmouk, queuing to receive food supplies, in Damascus, Syria, on January 31, 2014. A United Nations official is calling on warring sides in Syria to allow aid workers to resume distribution of food and medicine in a Palestinian district of Damascus. The call comes as U.N. Secretary General Ban Ki-Moon urged Syrian government to authorize more humanitarian staff to work inside the country, devastated by its 3-year-old conflict. (AP Photo/UNRWA)

From In Syria: Three Years of War, one of 37 photos. This picture taken the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) shows residents of the besieged Palestinian camp of Yarmouk, queuing to receive food supplies, in Damascus, Syria, on January 31, 2014. A United Nations official is calling on warring sides in Syria to allow aid workers to resume distribution of food and medicine in a Palestinian district of Damascus. The call comes as U.N. Secretary General Ban Ki-Moon urged Syrian government to authorize more humanitarian staff to work inside the country, devastated by its 3-year-old conflict. (AP Photo/UNRWA)

September 20, 2013
From Non-Chemical Warfare: Violence Continues in Syria, one of 41 photos. A member of the ‘Ansar Dimachk’ Brigade, part of the Asood Allah Brigade which operates under the Free Syrian Army, uses an iPad during preparations to fire a homemade mortar at one of the battlefronts in Joubar, a suburb of Damascus, Syria, on September 15, 2013. (Reuters/Mohamed Abdullah)

From Non-Chemical Warfare: Violence Continues in Syria, one of 41 photos. A member of the ‘Ansar Dimachk’ Brigade, part of the Asood Allah Brigade which operates under the Free Syrian Army, uses an iPad during preparations to fire a homemade mortar at one of the battlefronts in Joubar, a suburb of Damascus, Syria, on September 15, 2013. (Reuters/Mohamed Abdullah)

July 3, 2013
From The Battle of Gettysburg: 150 Years Ago, one of 33 photos. Here, Confederate Civil War reenactors launch an evening attack during a three-day Battle of Gettysburg re-enactment on June 29, 2013 in Gettysburg, Pennsylvania. Some 8,000 reenactors from the Blue Gray Alliance participated in events marking the 150th anniversary of the July 1-3, 1863 Battle of Gettysburg. Confederate General Robert E. Lee’s Army of Northern Virginia was defeated at Gettysburg, considered the turning point in the American Civil War. (John Moore/Getty Images)

From The Battle of Gettysburg: 150 Years Ago, one of 33 photos. Here, Confederate Civil War reenactors launch an evening attack during a three-day Battle of Gettysburg re-enactment on June 29, 2013 in Gettysburg, Pennsylvania. Some 8,000 reenactors from the Blue Gray Alliance participated in events marking the 150th anniversary of the July 1-3, 1863 Battle of Gettysburg. Confederate General Robert E. Lee’s Army of Northern Virginia was defeated at Gettysburg, considered the turning point in the American Civil War. (John Moore/Getty Images)

December 19, 2012
From Syria’s Long, Destructive Civil War, one of 40 photos. Smoke rises in the Hanano and Bustan al-Basha districts in the northern city of Aleppo as fighting continued through the night, on December 1, 2012. A large rebel force launched an offensive on one of the few army bases in northwestern Syria still in the hands of loyalist forces and as fighting near Damascus closed the main road to the airport. (Javier Manzano/AFP/Getty Images)

From Syria’s Long, Destructive Civil War, one of 40 photos. Smoke rises in the Hanano and Bustan al-Basha districts in the northern city of Aleppo as fighting continued through the night, on December 1, 2012. A large rebel force launched an offensive on one of the few army bases in northwestern Syria still in the hands of loyalist forces and as fighting near Damascus closed the main road to the airport. (Javier Manzano/AFP/Getty Images)

October 4, 2012
From Destruction Comes to Aleppo, one of 36 photos. A Syrian man cries while holding the body of his son near Dar El Shifa hospital in Aleppo, Syria, on October 3, 2012. Three suicide bombers detonated cars packed with explosives in a government-controlled area of the battleground Syrian city of Aleppo on Wednesday, killing at least 34 people, leveling buildings and trapping survivors under the rubble, state TV said. More than 120 people were injured, the government said. (AP Photo/Manu Brabo)

From Destruction Comes to Aleppo, one of 36 photos. A Syrian man cries while holding the body of his son near Dar El Shifa hospital in Aleppo, Syria, on October 3, 2012. Three suicide bombers detonated cars packed with explosives in a government-controlled area of the battleground Syrian city of Aleppo on Wednesday, killing at least 34 people, leveling buildings and trapping survivors under the rubble, state TV said. More than 120 people were injured, the government said. (AP Photo/Manu Brabo)

February 10, 2012
From The Civil War, Part 3: The Stereographs, one of 20 stereo pairs, part of 3-part series. Photographer Timothy H. O’Sullivan took this photo, one half of a stereo view of Alfred R. Waud, artist of Harper’s Weekly, while he sketched on the battlefield near Gettysburg, Pennsylvania in July of 1863. To see this animate in 3-D, click through to photo #2 in the full entry. (Timothy H. O’Sullivan/LOC)

From The Civil War, Part 3: The Stereographs, one of 20 stereo pairs, part of 3-part series. Photographer Timothy H. O’Sullivan took this photo, one half of a stereo view of Alfred R. Waud, artist of Harper’s Weekly, while he sketched on the battlefield near Gettysburg, Pennsylvania in July of 1863. To see this animate in 3-D, click through to photo #2 in the full entry. (Timothy H. O’Sullivan/LOC)

February 9, 2012
From The Civil War, Part 2: The People, one of 48 photos, part of 3-part series. Abraham Lincoln, the 16th President of the United States, in a head-and-shoulders portrait taken by photographer Alexander Gardner on February 5, 1865. Traditionally called “last photograph of Lincoln from life”, this final photo in Lincoln’s last photo session was long thought to have been made on April 10, 1865, but more recent research has indicated the earlier date in February. The crack comes from the original negative, which was broken and discarded back in 1865. The entirety of the American Civil War took place while Lincoln was in office, starting a month after he was elected, and ending just days before his assassination in April of 1865. (LOC)

From The Civil War, Part 2: The People, one of 48 photos, part of 3-part series. Abraham Lincoln, the 16th President of the United States, in a head-and-shoulders portrait taken by photographer Alexander Gardner on February 5, 1865. Traditionally called “last photograph of Lincoln from life”, this final photo in Lincoln’s last photo session was long thought to have been made on April 10, 1865, but more recent research has indicated the earlier date in February. The crack comes from the original negative, which was broken and discarded back in 1865. The entirety of the American Civil War took place while Lincoln was in office, starting a month after he was elected, and ending just days before his assassination in April of 1865. (LOC)

February 8, 2012
From The Civil War, Part 1: The Places, one of 48 photos, part of a 3-part series. This September 1862 photo provided by the Library of Congress shows Allan Pinkerton on horseback during the Battle of Antietam, near Sharpsburg, Maryland. Before the outbreak of war, he had founded the Pinkerton National Detective Agency. In 1861, he famously foiled an alleged plot to assassinate president-elect Lincoln, and later served as the head of the Union Intelligence Service — the forerunner of the U.S. Secret Service. (AP Photo/Library of Congress, Alexander Gardner)

From The Civil War, Part 1: The Places, one of 48 photos, part of a 3-part series. This September 1862 photo provided by the Library of Congress shows Allan Pinkerton on horseback during the Battle of Antietam, near Sharpsburg, Maryland. Before the outbreak of war, he had founded the Pinkerton National Detective Agency. In 1861, he famously foiled an alleged plot to assassinate president-elect Lincoln, and later served as the head of the Union Intelligence Service — the forerunner of the U.S. Secret Service. (AP Photo/Library of Congress, Alexander Gardner)