Obviously he wrote many books ;)

The photos are from the five-volume book series "Schauplätze des Gebirgskrieges" by Walther Schaumann, published in the 1970s and 1980s. In these books, he describes the events of #WWI at various locations, accompanied by so many detailed tour suggestions.

Seems to be Type 3 fun

I often wonder if the sandbags dissolved on their own or not.