[2] Daily public transportation to the park is provided by Amtrak Thruway's 7 Route to Martinez station, Evans Transportation also provides daily service between a Courtyard by Marriott hotel (located adjacent to the northeastern border of the park) and Oakland International Airport.

[3] Six Flags Discovery Kingdom opened in 1968 as Marine World, a small zoo in Redwood City, California.

[6] In March 1987, actor William Shatner raised money for the California Rare and Endangered Species Preservation Fund by riding a killer whale at the park.

[8] Vallejo hired Premier Parks (now known as Six Flags Entertainment Corporation) to manage the property, upgrade it, and improve its attendance.

[citation needed] The number of amusement rides increased over the next few years, including the addition of several major roller coasters.

After the final operating day of the 1998 season, October 31, the park officially became Six Flags Marine World.

The park also began to show 7th Portal, a 3D comic book film by Stan Lee, in the DinoSphere Theater during this season.

Zonga's last season of operation was 2004; it then sat dormant until it was removed in 2006 and placed in the parking lot for storage.

The park also began showing Stargate SG3000 in its Iwerks 3D Turbo Theater, which finally received new branding and was no longer called DinoSphere.

[citation needed] On October 30, 2004, an accident on nearby I-80 caused power to go out in the park, resulting in several dozen riders getting stranded on roller coasters.

[22] In 2008, the park closed the IWerks 3D Turbo Theater due to escalating repair costs on the out-of-date operating system and hardware.

The park received its eighth roller coaster named Tony Hawk's Big Spin, which was located on the former Zonga concrete pad.

The ride featured a unique layout compared to the three other coasters which share the name, including a base frame instead of permanent concrete footers and a higher top speed.

[25] In 2012, the park added a steel Premier Rides roller coaster called Superman: Ultimate Flight.

[26] It is the tallest roller coaster inversion west of the Mississippi River, measuring 150 feet (46 m) in height.

In 2014, Six Flags Discovery Kingdom held a press event for the new Tsunami Soaker water ride, during which the park announced a May 31, 2014 opening to the general public.

[29][needs update] On August 28, 2014, Discovery Kingdom announced the new Dare Devil Chaos Coaster flat ride for the 2015 season.

[30] It is a standard 22M Larson Superloop pendulum flat ride that rocks riders back and forth inside a 360 degree loop.

[33] On September 3, 2015, the park announced their tenth major thrill coaster, The Joker, which is a hybrid transformation of Roar.

The coaster features a 100-foot height, a 78-degree drop, and three inversions including the world's first step-up under flip inverted roll.

[34] In February 2016, the park opened Pacific Rim 5-D, an in-theater, special effects 3D movie, on a limited and trial-run basis.

[36] Each fall, Discovery Kingdom opens Fright Fest for Halloween, consisting of six haunted houses, scare zones, and many ghouls that are added throughout the park.

The scare zone is located between Ocean Discovery and the entry plaza, where cockroach eating contests are held.

That year, Discovery Kingdom also featured the world's largest Christmas tree as part of the celebration.