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
MKM steel MKM steel MKM steel, an alloy containing nickel and aluminum, was developed in 1931 by the Japanese metallurgist Tokuhichi Mishima. While conducting research into the properties of nickel, Mishima discovered that a strongly magnetic steel could be created by adding aluminum to non-magnetic nickel steel. The developers claim MKM steel is tough and durable, inexpensive to produce, maintains strong magnetism when miniaturized and can produce a stable magnetic force in spite of temperature changes or vibration. MKM steel is similar to Alnico. MKM is an acronym for Mitsujima ka magnetic, 'Mitsujima ka' being the name of the inventor's childhood home.