Twisted Colossus is a steel roller coaster under renovation at Six Flags Magic Mountain in Valencia, California. Originally designed and built by International Amusement Devices, the roller coaster opened as Colossus on June 29, 1978. It was the tallest and fastest wooden roller coaster in the world and the first with two drops greater than 100 feet (30 m). Colossus became well known after appearances in film and television, including the box-office hit National Lampoon's Vacation. After more than 36 years in operation, Six Flags announced in 2014 that the roller coaster would be closed permanently on August 16, 2014.

Within two weeks of its closure, Six Flags announced that the coaster would reemerge in 2015 as a hybrid wood and steel roller coaster named Twisted Colossus. It is being renovated by Rocky Mountain Construction to feature barrel roll inversions, a near-vertical drop, and dueling tracks that allow riders on different trains to race from start to finish.

For their next attraction to debut in 1978, Magic Mountain wanted a wooden roller coaster for the classic "rumble and sway" experience that they felt was missing from steel coasters. A member of the design team traveled to Mexico City to study Montaña Rusa – the largest wooden roller coaster in the world at the time – in order to help plan for the project.

The design was finalized in May 1977, and construction began a few months later in August. During construction, a tornado caused part of the structure to collapse, but the roller coaster was still completed on schedule. At a final cost of $7 million, Colossus opened to the public on June 29, 1978. It was the tallest and fastest roller coaster in the world, as well as the first to feature two drops over 100 feet (30 m).

Modifications: Colossus underwent a number of changes over the years. The "speed hill" between the second drop and the double-up hill was reprofiled in 1979. In 1987, the original trains supplied by Philadelphia Toboggan Company were replaced with ones from Morgan Manufacturing. The valley between the coaster's pair of camelback hills was leveled off and received block brakes in 1991.

During the Halloween season, the coaster's web-like structure was accompanied by a giant black spider, and the height restriction became 54 inches (1,400 mm). The cars on one side of the track were also run backwards, using the old trains from the now defunct Psyclone roller coaster.On August 29, 2013, Six Flags Magic Mountain announced that they would run Colossus backwards for a limited time during the 2014 season.

Renovations: During the 2014 season, Six Flags Magic Mountain announced that Colossus would close permanently on August 16, 2014. On August 4, 2014, the park held a 36-hour riding marathon event on the roller coaster as a way for the public to say goodbye to one of the park's staples. Out of 24 participants, six completed the marathon of 328 laps around the track in 45-minute intervals.

Less than two weeks after the ride closed, Six Flags announced that Colossus would reopen in 2015 as Twisted Colossus following a renovation by Rocky Mountain Construction. The company is planning to add their patented I-Box technology to the ride, also known as Iron Horse, which converts the wooden track to steel while retaining the original wooden structure. The hybrid retrofitting is becoming a popular trend at amusement parks around the world looking to extend the life of aging wooden coasters.

Colossus: The previous configuration of the roller coaster featured two drops greater than 100 feet (30 m); the first drop was 115 feet (35 m) and the second was 105 feet (32 m). The ride spanned two and a half minutes and reached speeds up to 62 miles per hour (100 km/h).

Twisted Colossus: Twisted Colossus will feature two 128 ft lift hills, two Inversions, and a 80° drop. It will also include a "high-five" element.

Colossus was nearing completion in May 1978 when it was used as a backdrop for fight scenes in the NBC TV movie Kiss Meets the Phantom of the Park. In 1983, it was featured in the film National Lampoon's Vacation (Starring Chevy Chase and Chris Farley) as “Screemy Meemy.”

In the sitcom Step by Step, Colossus is the roller coaster that the Lambert-Foster family rides in the opening sequence. The roller coaster was also seen in television episodes of Wild & Crazy Kids, Doogie Howser, M.D.,Knight Rider, Wonder Woman, and The A-Team. The film Zapped! featured the ride when protagonists Barney and Bernadette visit Magic Land (Six Flags Magic Mountain).

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