Great American Scream Machine was a steel roller coaster located at Six Flags Great Adventure. The 173-foot (53 m) tall ride was built in 1989 as the fastest looping roller coaster in the world, reaching speeds up to 68 mph (109 km/h). It was designed by Ron Toomer and built by Arrow Dynamics, which built its sister coasters Shockwave (dismantled in 2002) at Six Flags Great America in Gurnee, Illinois and Viper at Six Flags Magic Mountain in Valencia, California. All three coasters have three loops after the lift hill, a batwing (also known as a boomerang), and a double corkscrew. Scream Machine succeeded its sister coaster Shockwave as the tallest and fastest looping coaster in the world, but relinquished the claim to its other sister coaster Viper. Both Shockwave and Scream Machine only held the claim for one year.