Dr. Diabolical's Cliffhanger, the world's steepest B&M dive coaster, officially opened on July 30, 2022 at Six Flags Fiesta Texas. The park's 11th roller coaster, Dr. Diabolical's Cliffhanger reaches speeds of 60 miles per hour and a height of 150 feet. Riders are hung over the attraction's 95-degree first drop before plummeting down and into two inversions.