The images offer an insight into varied and contrasting aspects of the conflict and its fall-out.

In the picture above, for example, U.S. soldiers model international gas mask designs at the Chemical Development Laboratory in Philadelphia, after the end of the war.

Protection against chemical weapons was a concern during a conflict in which poison gas was used to devastating effect.

The designs shown here range from the relatively simple “British black veil mask” (centre, far left) to the much bulkier “British motor corps mask” (bottom, third right).