American soldiers getting their bowls of chocolate and rolls in the American Red Cross canteen at Toulouse, France, circa 1918.

An undated archive picture shows Germans soldiers, captured during the Battle of Verdun, taking off their clothes for a body search by French soldiers, in Eastern France. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

A British Mark IV tank falls into a trench at Ribecourt la Tour, near Cambrai, during the Battle of Cambrai, November 20, 1917. World War One pioneered many "firsts" in technological, scientific and societal innovations. Tanks were invented as a means of breaking the trench warfare stalemate.

Cyclists of the 2nd Battalion, Canadian Expeditionary Force pose at Scottish Lines near Poperinghe, not far from Ypres, France, June 1916.

Canadian soldiers leave the trenches during the Battle of the Somme, 1916.

German prisoners carry a stretcher during the Battle of the Somme. This week marks the 100th anniversary of the first Battle of the Somme -- one of the bloodiest battles in history, which claimed 1,250,000 casualties between July and November 1916.

American soldiers react to a gas attack in an undated photo, likely used for training purposes.

Wounded lie in an American field hospital in Auteuil, Paris, France.

American soldiers practice throwing hand grenades at enemy positions in Choloy, France, August 1, 1918.

U.S. soldiers of the 82nd Division stand in formation at Camp Gordon, Georgia in 1917 for service overseas. The division would later become the legendary 82nd Airborne Division.

An archive picture shows Field Marshal Horatio Herbert Kitchener (2nd L) meeting French General Albert Baratier (R), on horseback, as French Marshal Joseph Joffre looks on (2nd R), on the Champagne front, Eastern France in 1915. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

American soldiers move equipment along a dirt road in Saint-Ouen-les-Parey, France, February 1918.

American, British, French, and German gas masks.

American soldiers keep watch in a trench in France.

An archive picture shows French cyclists of the Cavalry Corps, on the Champagne Front, Eastern France September 22, 1915. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

British soldiers wait in the trenches on the Western Front during the First World War in this undated file photo. World War One pioneered many "firsts" in technological, scientific and societal innovations. Steel helmets were used for the first time as protective headgear for soldiers. Field telephones and wireless communications were regularly used for the first time to coordinate military movements.

A crowd in Times Square hold up copies of newspapers with a headline about the signing of the Armistice to end World War One, in New York, U.S., November 11, 1918.

A photo described as showing French troopers under General Gouraud driving back Germans with their machine guns amongst the ruins of a cathedral near the Marne, France, circa 1918.

German prisoners in a French prison camp, circa 1917 - 1919.

Shrapnel bursts over a reserve trench above Canadian lines during the Battle of the Somme, in France, 1916.

Two gas shells explode near Canadian lines during the Battle of the Somme, France, October, 1916.

Wounded are dressed in a trench during the Courcelette operation of the Battle of the Somme, September 1916.

An American gun crew from Regimental Headquarters Company, 23rd Infantry, fires a 37mm gun during an advance against German entrenched positions.

American soldiers of the Machine Gun Battalion, Company G, Second Brigade, gather around an outdoor kitchen in Hermitage, France, March 11, 1918.

U.S. Army soldiers playing baseball in France in 1917.

An undated archive picture shows German soldiers (rear) offering to surrender to French troops, seen from a listening post in a trench at Massiges, northeastern France. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

American soldiers from the 1st Division during their journey overseas.

American troops march down a road in France.

U.S. soldiers of the American Expeditionary Force are seen during a pause in fighting Courtesy U.S. Army.

An archive picture shows captured Germans soldiers marching through Chalons en Champagne, Eastern France September 1915. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of the WWI.

An archive picture shows a priest conducting mass for French soldiers on the Champagne front, eastern France in 1915. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

An American Expeditionary Force doctor tends to an injured American soldier immediately behind the first trench line in France, in 1919.

U.S. Marines form a line in France.

An undated archive picture shows injured soldiers arriving at a hospital before being evacuated on the Champagne front, eastern France. A Viscount in the Armoured Cavalry Branch of the French Army left behind a collection of hundreds of glass plates taken during World War One (WWI) that have never before been published. The images, by an unknown photographer, show the daily life of soldiers in the trenches, destruction of towns and military leaders. The year 2014 marks the 100th anniversary of the start of WWI.

A U.S. Marine leads training on a shooting range in France.

American troops undergo grenade gun training in France.