elephant cage
n.— «On base is a maze of wire and steel rods laid out over an area larger than a football field. Local people call it “the elephant cage.” It houses one of the most important intelligence-gathering operations the U.S. military is conducting in the Indochina war.» —“GIs at a Secret Base—Plenty of Time to Worry” by Michael Morrow in Ramasun, Northeastern Thailand Washington Post, Times Herald Sept. 14, 1972. (source: Double-Tongued Dictionary)