This area was once the site of one of Alum Rock Park's most popular attractions, the Natatorium, a large indoor swimming pool. Built about 1912, it attracted over 35,000 swimmers each summer season. For about 20 cents, park visitors could swim in the heated waters of the 45-foot-wide and 90-foot-long pool. The pool also boasted a long, straight slide, a one-meter diving board, and three diving platforms for those who were looking for more excitement with their swim.
The Natatorium was a full-service recreation facility with a spectator's gallery, swimsuit and towel rentals, and an in-house laundry to keep everything clean and sanitary. The building also contained 51 mineral baths. These individual, tiled rooms could be rented for a small fee. Park visitors could enjoy a peaceful soak in a tub of hot sulfur water piped in from the park's natural mineral springs. For over 60 years, people came from all over the valley to play at Alum Rock Park and swim at the Natatorium.
The Natatorium was closed after the 1970 summer season. Time had taken its toll on the old facilities and the structure was no longer safe or sanitary. The Park Commissioners and the City Council decided to tear down the building during the mid-1970s. Today, swimmers have access to many different neighborhood pools during the hot summer months, but none will ever replace the old Alum Rock Park Natatorium.