Aquatic Park Historic District is a National Historic Landmark and building complex located on the San Francisco Bay waterfront within San Francisco Maritime National Historical Park. The district includes a beach, bathhouse, municipal pier, restrooms, concessions stand, stadia, and two speaker towers. It was declared a National Historic Landmark in 1987, and added to the National Register of Historic Places on January 26, 1984. The park is located at the foot of Polk Street and is a minute's walk from the visitor center and Hyde Street Pier. Its beach is one of the cleanest in the state.