What is the worlds talest roller coasters?

The world's tallest roller coaster is Kingda Ka at Six Flags Great Adventure in Jackson, New Jersey, United States. It is a steel roller coaster that has a height of 456 feet (139 m). The ride opened in 2005 and has a maximum speed of 128 miles per hour (206 km/h). Kingda Ka was designed by Werner Stengel, who is also known for designing other roller coasters such as Superman: Escape from Krypton and The Riddler's Revenge.