In 1896, the Sutro Baths was opened to the public as the world's largest indoor swimming pool establishment. Built on the western side of San Francisco by former mayor of San Francisco, Adolph Sutro, the vast glass, iron, wood, and concrete structure was mostly hidden in, and literally filled, a small beach inlet below the Cliff House which was also owned by Adolph Sutro at the time.
A visitor to the baths not only had a choice of 7 different swimming pools — one fresh water and six salt water baths ranging in temperatures — but could 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 2 million gallons of water in about an hour.