The circuit was designed in 1969; it was built from 1970 and 1972, and inaugurated that year. Its initial length was 3.488 km (2.167 miles) and only had a small, open pit area. This version of the circuit hosted three editions of the San Marino motorcycle Grand Prix, from the 1985 season to the 1987 season. In 1993 it was modified for the first time: the track length was increased to 4.060 km (2.523 miles), with the possibility to race both the long and the old short loop; moreover, new facilities and new pit garages were built. It was at Misano during the 1993 Italian Grand Prix that the defending 500 cc World Champion Wayne Rainey's career ended after he fell and suffered a broken spine. Between 1996 and 2001 all facilities were improved further, adding more pits and stands. In 2005, a new access point to the circuit was built, Via Daijiro Kato, in honor of the late Japanese rider, killed during the 2003 Japanese Grand Prix, whose in-season race home was in the Portoverde frazione of Misano Adriatico.