Ecce Puer (See the child) by Medardo Rosso, 1906.
Lee Bontecou, Untitled, 1937. Wonderfully 3D effect done with canvas
Beatifully stylised Bird Swallowing A Fish by Henri Gaudier-Brzeska, 1914.
This piece, Der Rächer by Ernst Barlach from October 1914 is a good reminder that Germans at that time didn't see themselves as evil invaders but as righteous avengers. The avenger is holding a saex, an ancient Germanic sword type. I feel there's an uncanny resemblance between the face and that of then Emperor Wilhelm II.
Barlach's enthusiasm for the war quickly wore off on the front and he returned as a pacifist. His post war work includes many commemorative signs at war cemeteries. His work was later labeled as Entartete Kunst by the Nazis. Just like Käthe Kollwitz, who lost her son in the Great War. This is her Turm der Mutter from 1937.