On March 14, 1896, the Sutro Baths were opened to the public as the world's largest indoor swimming pool establishment. The baths were built on the sleepy western side of San Francisco by wealthy entrepreneur and former mayor of San Francisco
(1894–1896), Adolph Sutro
. The vast glass, iron, wood, and reinforced concrete structure was mostly hidden, and filled a small beach inlet below the Cliff House
, also owned by Adolph Sutro at the time. Both the Cliff House and the former baths site are now a part of the Golden Gate National Recreation Area
and operated by the United States National Park Service
A visitor to the baths not only had a choice of seven different swimming pools—one fresh water and six salt water baths ranging in temperatures—but could also visit a museum displaying Sutro's large and varied personal collection of artifacts from his travels, a concert hall, seating for 8,000, and, at one time, an ice skating rink. During high tides, water would flow directly into the pools from the nearby ocean, recycling the two million US gallons (7,600 m³) of water in about an hour. During low tides, a powerful turbine water pump, built inside a cave at sea level, could be switched on from a control room and could fill the tanks at a rate of 6,000 US gallons a minute (380 L/s), recycling all the water in five hours.
The baths were once serviced by a rail line, the Ferries and Cliff House Railroad, which ran along the cliffs of Lands End overlooking the Golden Gate
. The route ran from the baths to a terminal at California Street and Central Avenue (now Presidio Avenue).
The baths struggled for years, mostly due to the very high operating and maintenance costs. Shortly after closing, a fire in 1966 destroyed the building while it was in the process of being demolished. All that remains of the site are concrete walls, blocked off stairs and passageways, and a tunnel with a deep crevice in the middle. The Sutro Bath ruins are open to the public, but a warning sign advises strict caution, as visitors have been swept off by large waves and drowned at the site.