Americans Underground: Secret City of WWI (2017)

Plot

Beneath a tranquil farm field in Northern France lies an extraordinary underground city, a refuge for soldiers from both sides during World War I. This hidden network of shelters, part of a larger system along a 45-mile stretch of the Western Front, is brought to light by American explorer and photographer Jeff Gusky. As he uncovers this forgotten world, Gusky embarks on a poignant journey to link the names of American soldiers inscribed in the limestone walls to their descendants, bridging the past with the present in a powerful exploration of memory and loss.