I have lived in the Bay Area all my life. I have been to the Japanese Tea Garden in Golden Gate Park many times but learned about things I had never noticed when I went there on a San Francisco City Guides tour. This tour lead by a very knowledgeable volunteer was great. They give free tours of places all over the city.
I had never been to Alcatraz and finally made it over to the "rock". The Alcatraz Historic Gardens Project preserves, rebuilds, and maintains the gardens created by those who lived on the island, and interprets their history. They have docent led tours that explain the gardens and tell the amazing story of the restoration.