The end of an era for roller coaster riders

Once the tallest and fastest roller coaster in the world, the Colossus at Six Flags Magic Mountain in Valencia, California, is being retired.

The wooden coaster, built in 1978, which stands 125 feet tall and whisks riders at more than 60 mph, will take its last passengers on Saturday, which is National Roller Coaster Day, according to Six Flags.

Six Flags Colossus Roller Coaster.
Source: Wikipedia
Six Flags Colossus Roller Coaster.

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The Colossus has since been eclipsed by the Goliath at Six Flags Great America in Gurnee, Illinois, which travels at up to 72 mph and has a 180-foot drop, the biggest of any wooden roller coaster in the world, according to David Lipnicky spokesman for American Coaster Enthusiasts.

But the tallest coaster in the world is the Kingda Ka, at Six Flags Great Adventure in Jackson, New Jersey, which stands 456 feet tall. And traveling at speeds up to 128 mph, it's the fastest coaster in North America, Lipnicky said.

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But a new record is in the making in Orlando, Florida. U.S. Thrill Rides and engineers at S&S Worldwide are building a more than 500 foot tall coaster called the Skyscraper at Skyplex. The ride is based on a so-called Polercoaster design, in which a track wraps around a tower. That coaster is expected to open in 2016, according to Michael Kitchen, president of U.S. Thrill Rides.

—By CNBC's Althea Chang