Free Walking Sightseeing Tour #6 in San Francisco, United States

The GLBT Historical Society maintains an extensive collection of archival materials, artifacts and graphic arts relating to the history of LGBT people in the United States, with a focus on the LGBT communities of San Francisco and Northern California.

Wikipedia: GLBT Historical Society (EN), Website, Facebook, Instagram, Youtube

Harvey Milk Plaza is a transit plaza at the Castro Muni Metro subway station commemorating Harvey Milk, in San Francisco's Castro District, in the U.S. state of California.

Wikipedia: Harvey Milk Plaza (EN), Website

The Pink Triangle Park is a triangle-shaped mini-park located in the Castro District of San Francisco, California. The park is less than 4,000 square feet (370 m2) and faces Market Street with 17th Street to its back. The park sits directly above the Castro Street Station of Muni Metro, across from Harvey Milk Plaza. It is the first permanent, free-standing memorial in America dedicated to the thousands of persecuted homosexuals in Nazi Germany during the Holocaust of World War II.

Wikipedia: Pink Triangle Park (EN), Website

The Auxiliary Water Supply System is a high pressure water supply network built for the city of San Francisco in response to the failure of the existing emergency water system during the 1906 earthquake. It was originally proposed by San Francisco Fire Department chief engineer Dennis T. Sullivan in 1903, with construction beginning in 1909 and finishing in 1913. The system is made up of a collection of water reservoirs, pump stations, cisterns, suction connections and fireboats. While the system can use both fresh or salt water, it is preferential to not use salt water, as it commonly causes galvanic corrosion in fire equipment.

Wikipedia: San Francisco Fire Department Auxiliary Water Supply System (EN)

The Twin Peaks are two prominent hills with an elevation of about 925 feet (282 m) located near the geographic center of San Francisco, California. The Twin Peaks are the second and third highest mountains in the city; only 928 foot (283 m) Mount Davidson is higher within San Francisco city limits.

Wikipedia: Twin Peaks (San Francisco) (EN)