sprawling military bunker , World War I bunker , a secret location deep within a French forest. 龐大的軍事掩體 ， 第一次世界大戰的沙坑 ， 法國的森林深處的一個秘密地點。

Inside France's secret World War I bunker: Urban explorers find wartime weapons stowed away in underground quarry | Mail Online http://www.dailymail.co.uk/news/article-2138544/Inside-Frances-secret-World-War-I-bunker-Urban-explorers-wartime-weapons-stowed-away-underground-quarry.html