Photograph of aerial view of San Gabriel Dam No.1, ca.1920. In the far background at center, a large body of water calmly sits between two large mountain ranges. On the left bank of the calm river, a small group of buildings are visible near the water's edge. As the body of water moves closer center, a large slanted dam is visible, partially obscured by a large hillside. The dam is positioned at a narrow choke point between the two mountain passes. The face of the dam is separated into noticeable layers, and it is also slightly slanted. At the base of the dam near one of the mountain ranges, a small building can be seen sitting near the water's edge. The elongated building shows at least four doorways from the side. A moving river is visible at the base of the dam cutting through the mountain passes. To the left of this river, a small winding road curves along the base of the mountain.