This acoustic sculpture was constructed in 1986 by Peter Richards, a senior artist at the Exploratorium museum, and sculptor and master stone mason George Gonzalez. It is dedicated to the memory of the Exploratorium founder, Frank Oppenheimer.
The small jetty you're on was constructed from the material of a demolished cemetery, and the same gravestones went into making the organ. Sit on the stones and spend awhile listening intently to the subtle and otherworldly sounds of waves beating against 25 PVC pipes. Put your ear to one of the hearing tubes, or snuggle into the booth where the sound comes from three sides.
If you are lucky the fog will come up and hide the rest of the world, but if you are not try to console yourself with the fine view of Alcatraz and Golden Gate bridge.