Fleishhacker Pool

Beneath the asphalt parking lot of the San Francisco Zoo lies the footprint of a record-breaking aquatic giant. Opened in 1925, the Fleishhacker Pool was once the largest outdoor saltwater swimming pool in the world, stretching one thousand feet in length. It held six and a half million gallons of ocean water, which was pumped directly from the Pacific and heated to accommodate swimmers. The scale of the basin was so vast that lifeguards were required to patrol the water in wooden rowboats to keep an eye on the crowd.