Photograph of cars lined up outside a Customs House at San Ysidro, south of San Diego, [s.d.]. The low wooden building can be seen at right, while a dirt road runs from the foreground to the background at left. Several early-model automobiles can be seen on the road, facing towards the background. A single tree can be seen near the covered front porch of the customs building at center.; Legible signs include, from left: "U.S. Customs", "U.S. Immigration Service", "Stop", "U.S. Customs House", and "Warning! Do not attempt to carry Liquor into the United States".