<Tr> <Td_colspan="2"> Kingda Ka at RCDB Pictures of Kingda Ka at RCDB </Td> </Tr> <P> Kingda Ka is a steel accelerator roller coaster located at Six Flags Great Adventure in Jackson, New Jersey . It is the world's tallest roller coaster, the world's second fastest roller coaster, and was the second strata coaster ever built . It was built by Stakotra, a subcontractor to Intamin . Riders have to be at least 54" tall in order to be able to get on the roller coaster . </P> <P> The train is launched by a hydraulic launch mechanism to 128 miles per hour (206 km / h) in 3.5 seconds . At the end of the launch track, the train climbs the main top hat tower, reaching a height of 456 feet (139 m) and spanning over a 3,118 - foot - long (950 m) track by the end of the ride . </P> <P> Plans to build Kingda Ka were announced on September 10, 2003, at an event held for roller coaster enthusiasts and the media . The event revealed the park's goal to build "the tallest and fastest roller coaster on earth", reaching 456 feet (139 m) and accelerating up to 128 miles per hour (206 km / h) in 3.5 seconds . On January 13, 2005, Kingda Ka's tower construction was completed, and on May 21, 2005, the ride opened to the public . Kingda Ka became the "tallest" and "fastest" roller coaster in the world, taking both world records from Top Thrill Dragster at Cedar Point . It lost the title of world's fastest when Formula Rossa at Ferrari World opened in November 2010 . Intamin designed both Kingda Ka and Top Thrill Dragster, and the two share a similar design and layout that differs primarily by the theme and the additional hill featured on Kingda Ka . Both rides were built by Stakotra and installed by Martin & Vleminckx . </P>

How tall is the drop at six flags