Millennium Force design and development phases of Millennium Force took place over five years. The first rumors that a new record-breaking roller coaster would be built at Cedar Point, which included speculation about a ten inversion roller coaster from Bolliger & Mabillard and an Arrow Dynamics MegaLooper, began circulating in early 1998. A roller coaster from D. H. Morgan Manufacturing was also rumored. On July 2, 1999, Cedar Fair Entertainment Company filed a trademark for the name Millennium Force, which raised more speculation about what the ride would be like. About a week later, the first track pieces were seen at the
Kingda Ka brake fins in the launch section keep fast-moving trains from returning all the way back to the station during failed attempts to complete the tophat element. The incident caused an unexpected stress on a number of fins, bending them forward. Not all required replacement, but there were more damaged brake fins than Six Flags had replacements for. Extra brake fins had to be ordered from the manufacturer, Intamin in Switzerland, and the ride had to undergo thorough testing following the repair. Kingda Ka reopened on August 4. Kingda Ka was struck by lightning in May 2009 and suffered serious damage.