We did not attend this tour of privately-owned public open spaces in San Francisco developed by SPUR. A relative did, with a design class from Merritt Horticulture Department. Of the tour, she said, "It makes a great afternoon walk downtown- some are great- some not- but interesting all the same."
Privately-owned public open space is also known as POPOS. Most POPOS were created as a result of "incentive zoning," i.e. developers could build more floor space if they provided outdoor and indoor open space accessible to the public. Learn more about POPOS in Jerold Kayden's "Privately owned public space: the New York City experience." The City of New York's POPOS maps are available through its Department of City Planning.
Question: Do you know where the POPOS are in your city?