Another one from the trail.
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 western side of San Francisco by wealthy entrepreneur and former mayor of San Francisco (1894–1896), Adolph Sutro.
The structure 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, operated by the United States National Park Service. 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.