Photograph of large wind tunnel found at California Institute of Technology, ca.1920. To the left, two men can be seen standing at the edge of a large cylinder. The diameter of the cylinder is greater than the height of either man. Small ridges can be seen on the exterior of the cylinder. On the far left, the cylinder is attached to a large sphere in the wall. The cylinder is seen stretching to the far left into the immediate foreground. A large metal ring separates the section of the cylinder in the background from the section of the cylinder in the foreground. Near the men, a small window is visible on the side of the cylinder. Poles and other beams also are found adjacent to the object. In the immediate foreground, a large stepladder sits near the cylindrical tunnel.