Farm fields held many of these man-made terrain features - structures of cement, stone and steel that belched death and destruction against advancing troops. Some fitted snugly into contours of a hill slope in order better to escape air detection. Others stood boldly in fields, seemingly defiant, with only a casual horizontal cover of foliage. Some were taken while in process of construction. All had one purpose and one common design, which was to hurl out a message of death.