One hundred years ago today, Britain declared war on Germany, thereby entering World War I. The day before, Germany had declared war on France. Before long, the world’s nations would be pitted against each other in a grueling conflict that would eventually take the lives of more than nine million soldiers.The iconic trenches of World War I were themselves an “unforeseen enemy,” though. The unceasing machine-gun fire led to a fate that was, at the time, almost as bad as death. Western front soldiers who popped their heads above their trenches would come back down with a nose, jaw, or even an entire face missing.