Whizzer, originally named Willard's Whizzer, is a steel roller coaster located at Six Flags Great America in Gurnee, Illinois, United States. Designed by Werner Stengel and built by Anton Schwarzkopf, the Speedracer model was one of two identical roller coasters built for the Marriott Corporation in time for the debut of their Great America parks in 1976. Whizzer is the last remaining Speedracer roller coaster in the world.