Description: On 24 July the tanker Empire Traveller discharged the first gasoline at Cherbourg, unloading at the long breakwater in the outer harbor-the Digue de Querqueville. The French and later the Germans had discharged gasoline and other POL supplies through a nine-inch pipeline running along the Digue to two nearby tank farms at the large Depot Cotier du Petrole and the somewhat smaller one at Sunic. In the same neighborhood was a tank farm at Hainneville, which the French Navy had used to store diesel fuel. The fourth farm the Americans discovered was underground, so cleverly concealed that even few Frenchmen knew of its existence. The French had built the installation, Les Couplets, in 1938 at the time of the Maginot Line construction. Double garage doors of an innocent-looking two story house facing the Rue de la Paix, which skirted the harbor between Cherbourg and Querqueville, opened on a 600-yard tunnel leading to four huge storage tanks located in a hollow carved out of a small mountain; thirty-eight feet of solid granite overhead made the tanks impervious to air attacks.