It’s surprising how many locals have never been to the Wave Organ; many don’t even know where it is. This “acoustic sculpture” is actually a huge marble-and-granite musical instrument created in 1986 by the Exploratorium’s senior artist Peter Richards and master stone mason George Gonzales. This surprise is located on a jetty behind the Golden Gate Yacht Club; follow Lyon Street toward the water from where it meets Marina Boulevard, continue as it becomes Yacht Road and go all the way out to the end of the jetty. Extending into the bay at various heights, the Wave Organ’s 25 pipes make noise whenever the Pacific’s waves flow in and out of them. Hold your ear close to the pipes and their ports to best appreciate their full range of sound. The organ is most active acoustically during high tide and becomes subtler as the water level drops. Call it mood music.