While the link is a rather interesting way of navigating through Philip Glass' music, the image above is a stereoscope of "The Glass Engine", exhibited at The Great Central Fair, Philadelphia, Pennsylvania in 1864. The fair was held by the Philadelphia branch of the United States Sanitary Commission, and was used to raise funds for providing Union soldiers in the Civil War with basic necessities and medical supplies.
... and, speaking of the Civil War, Philip Glass will be nearby in San Francisco in October, with the world premiere of his new opera, "Appomattox" ... featuring the operatic debuts of Robert E. Lee, Ulysses S. Grant, and Abraham Lincoln... or at least close facsimiles. There are also going to be over a dozen Glass-oriented events going on in the Bay Area, including Glass performing pieces for piano and cello, and a Glass collaboration with Leonard Cohen.
So, yeah... no Glass shortage here. It's kinda like being N.Y.C. for a month.