Sources of images used for this section as they appear, left to right, top to bottom:
U534, Paul adams, Wikimedia
Toxic gat set (CAIS) bottle containing sulfur mustard, U.S. Army Chemical Materials Agency, Wikimedia commons
7.7 cm FK 16 CMHM Brantford 1, Balcer, Wikimedia
Dr1repl, David Merrett, Wikimedia
Maxim 08 15 Memorial de Verdun, Janmad, Wikimedia
Bundesarchiv Bild 136-B0560, Frankreich, Kavalleristen im Schützengraben, Tellgmann, Oscar, Wikimedia
British Mark IV Tadpole tank, Wikimedia