Pacific Ocean Park was a theme park on a pier extending into the Pacific Ocean in Santa Monica. At the very end of the park was Mystery Island, a South Seas-themed area with a volcano and a train ride.
Dedication on July 10th, 1958. Actress Mitzi Gaynor (from the film, South Pacific) was there to drop a lei into the waters and do the hula. See below...
It opened to the public on Saturday, July 28, 1958 with an attendance of 20,000. The next day, it drew 37,262, outperforming Disneyland's attendance that day!
Pacific Ocean Park closed in 1967, and was demolished in the mid-'70s.