Disneyland opened in 1955, but it wasn't Southern California's first theme park. Knott's Berry Farm had slowly been growing over the past 20 years from a sit-down chicken dinner restaurant to a Ghost Town-themed park with a variety of attractions. And in 1954, Marineland of the Pacific opened in Palos Verde — at the time the world's largest "oceanarium" park.
The initial success of Marineland provided a model for four UCLA graduates — George Millay, Milton Shedd, Dave Demotte and Ken Norris — to open another oceanarium down the coast in San Diego, after they decided their initial plan for an underwater restaurant with a marine show wasn't feasible. SeaWorld San Diego opened March 21, 1964. Located on the shore of San Diego's Mission Bay, reclaimed from a tidal marsh, the park is subject to substantial development restrictions from both the city and the California Coastal Commission, which limits how SeaWorld can develop the park to this day. For example, SeaWorld San Diego's version of the Manta roller coaster tops out at 30 feet, due to Coastal Commission restrictions.
Originally a 21-acre park, SeaWorld opened with sea lion and dolphin exhibits, but none of what would become its icon, killer whales. Fortunately, 1964 was a great year to open a theme park with dolphins, as the television show Flipper debuted that fall, making the species of marine mammal a national sensation. Unline rival Marineland's owners, SeaWorld's four owners aggressively reinvested their earnings back into the park, allowing it to expand and in just four years eclipse Marineland in annual attendance.
Shamu, the third orca (killer whale) ever captured — and the first healthy orca to be caught intentionally, came to the park in December 1965, after being caught earlier that year in Washington's Puget Sound by a Seattle aquarium. Shamu died in 1971, but her name continues to be used as the stage name for all of the theme park chain's orcas around the country.
SeaWorld became a publicly-traded corporation for the first time in 1968, which allowed the park to invest more money in expansion, and not just in San Diego. SeaWorld opened its second park, SeaWorld Ohio, in 1970, and SeaWorld Orlando in 1973. In 1971, SeaWorld's founders partnered with the Newhall Land Company to open a more traditional theme park, Magic Mountain, in that northern Los Angeles suburb. SeaWorld soon backed out, but if you put a SeaWorld map and a Magic Mountain map side by side, you'll see multiple similarities, including iconic observation towers near their entrances and meandering paths that look nothing like Disney's traditional "hub and spoke" layout.
In 1976, textbook publisher Harcourt Brace Jovanovich bought the three SeaWorld parks. HBJ continued to invest in the park's expansion, including a Shark Encounter, massive new Shamu Stadium and Penguin Encounter in San Diego. In 1987, HBJ bought and closed Marineland, bringing many of its marine mammals, including the park's famous orcas Corky and Orky, to the San Diego SeaWorld. (Corky continues to live and perform there today.)
After selling to HBJ, George Millay went on in 1977 to develop the nation's first major water park, Wet n' Wild in Orlando. The World Waterpark Association later declared him the "Father of the Waterpark" and the International Association of Amusement Parks and Attractions [IAAPA] inducted him into its Hall of Fame in 1994 for his role in developing both the oceanarium and waterpark industries.
Facing crippling levels of debt, Harcourt Brace Jovanovich sold its theme parks to Anheuser-Busch in 1989, which had experience operating animal-themed attractions with its Busch Gardens theme parks. Under Busch, SeaWorld San Diego continued to grow, adding the Wild Arctic ride and exhibit in 1997, the Shipwreck Rapids raft ride in 1999, and the combination flume ride/roller coaster Journey to Atlantis in 2004, in addition to updating to its killer whale, dolphin and sea lion shows every few years. Anheuser-Busch also owned the U.S. theme park rights to the Sesame Street characters, which allowed SeaWorld San Diego to open its Sesame Street Bay of Play kiddie-ride area in 2008.
In 2008, Belgian brewer InBev acquired Anheuser-Busch, and the next year sold the parks once again, this time to private equity firm The Blackstone Group, which also owned the Legoland theme parks and half of the Universal Orlando Resort. In 2012, SeaWorld San Diego opened its Manta roller coaster and the next year Blackstone offered another "initial" public offering of SeaWorld stock, making SeaWorld again a publicly-traded company.
Over the years and its several owners, SeaWorld helped developed many of what have become standard practices for the care and breeding of marine mammals in captivity, and SeaWorld animal care employees routinely lead or assist in the rescue, care, rehabilitation and reintroduction to the wild of injured marine mammals, seabirds and other wildlife. In 2012, SeaWorld debuted a television show on the (Disney-owned) ABC network, Sea Rescue, which documents many of the parks' animal rescue and rehabilitation efforts.
For the park's 50th anniversary in 2014, SeaWorld San Diego rebuilt its entrance plaza as "Explorers Reef," designed to look as though visitors are walking under a wave into the bottom of the ocean, with touch pools that allow visitors to make immediate contact with some of the park's marine animals.