From Animals to Zeppelins, this A-Z Guide helps viewers better understand the “War that Shaped the 20th Century.”

In WWI, the poster, previously a successful medium for commercial advertising, was recognized as a means of spreading national propaganda with near unlimited possibilities.

On Christmas Eve of 1914, along parts of the Western and Eastern fronts in Europe, a spontaneous truce was declared among the weary, entrenched combatants of World War I. Was this a miracle?

It unites us, divides us and is one of the most effective weapons in war: the control (and cooking) of food.

The Volunteers: Americans Join World War I examines the stories of the young men and women who transformed the meaning of volunteerism.

On November 11, 1918, after four years of horrific fighting and the loss of millions of lives, the guns on the Western Front fell silent.