Date: 21 July 2014
From the web page of the Spreckels Pavilion on the site of the Balboa Park: "John D. and Adolph Spreckels donated the Spreckels Organ, one of the world's largest outdoor pipe organs, to the City of San Diego in 1914 for the Panama-California Exposition. This unique organ contains 4,530 pipes ranging in length from the size of a pencil to 32 feet and is housed in an ornate vaulted structure with highly embellished gables. Since 1917, San Diego has had a civic organist, who performs free weekly Sunday concerts."
Another site where to see photos of the organ and information on the calendar of concerts: spreckelsorgan.org. Also, Wikipedia page on Claus Spreckels, the father of John and Adolph (Spreckels Sugar Company).
The main pavilion:
Dancers getting ready:
The main pavilion and its left wing:
Various views of the left wing:
Details of the beautiful pavilion at the end of the left wing (the right wing is identical):