Henry Stickley, Army Corps of Engineers

While many of the infantry troops on the front lines in World War I were riflemen, there were various roles and occupations in the service, including artillerymen, mortar crews, machine gunners, and more.  However, other soldiers had further specialized occupations.  Henry Stickley, seen here, was assigned to a different role.  The castle badge on the collar of his uniform indicates that he was a member of the Army Corps of Engineers.
Engineers fulfill a broad need of essential tasks within the army.  Depending on the need, engineers could be assigned to projects ranging from infrastructure development to laying obstacles to slow the advance of enemy troops.  Engineers have played a crucial role in every American war since the American Revolution, and World War I was no exception.
The unique environmental and combat conditions of the Western Front during World War I presented a host of challenges.  The need for engineers was so great that when the United States entered the war in 1917, the British and French militaries wanted engineers in particular be sent overseas.  In all, the United States sent thousands of army engineers to the Western Front.  
Engineers built roads, bridges, and even railroads that were vital for the transportation of people and supplies.  In addition, engineers were also active in fighting the enemy directly.  Engineers were heavily involved in developing and deploying American tanks on the battlefields, and played a key role in creating and defending against chemical weapons.

Why does the military require individuals with diverse skills?

Describe Henry Stickley's contribution to the war effort.