21. "Prince Max's Headquarter's" - Argonne Forest

Outerbridge was also able to travel to the site of the battle of Argonne Forest during his time with Mobile Unit 8. There he took photos of Prince Max's Headquarters, a secret German fort deep in the forest. The name "Prince Max" is most likely referring to Prince Maximillian of Baden, a German prince who served as Chancellor of the German Empire briefly in October and November of 1918. The name was likely given to the hidden fort as an inside joke or colloquialism.