Signs of the Civil War in Sant Felip Neri Square, Gothic Quarter, Barcelona, Catalonia, Spain, Europe

Tank, Cu Chi Tunnels, Ho Chi Minh City (Saigon), Vietnam, Indochina, Southeast Asia, Asia

Examples of booby traps used during Vietnam war, Cu Chi Tunnels, near Ho Chi Minh City (Saigon), Vietnam, Indochina, Southeast Asia, Asia

First World War rock tunnels on Mount Lagazuoi with Pelmo and Nuvolau peaks on background, aerial view, Natural Park of the Ampezzo Dolomites, Veneto, Italy, Europe

Jersey War Tunnels, German Underground Hospital, Jersey, Channel Islands, United Kingdom, Europe

Guernsey Underground German Military Hospital from World War Two, Channel Islands, United Kingdom

Trap with metal spikes, Viet Cong tunnel system in Cu Chi, Vietnam, Asia

Screening and model of the tunnel system in the open-air war museum in Cu Chi, South Vietnam, Vietnam, Southeast Asia, Asia

Old Syrian Army Bunker, Golan Heights, Israel