This article was oginally published by The Guardian by David Smith.
It redefined women's rights, race relations, civil liberties and America's role in the world. It caused twice as many American deaths as the Vietnam war. But there is no national memorial to it in Washington DC and, on Thursday, its centernary will pass with little fanfare.
On 6 April 1917, America declared war on Germany and charge into the first world war. After nearly three years of reluctance, its hand was forced by the sinking of neutral US ships by German submarines, and by Britain's interception of the so-called Zimmerman telegram revealing a German plot to persuade Mexico to wage war on the US.
America mustered more than 4.7 million service members with astonishing speed and suffered 53,402 battle deaths and 63,114 other deaths in service, many from Spanish flu. America's involvement was crucial to the Germans' defeat in 1918, profoundly shaping what came to be known as "the American century". READ MORE