Early history  The starting grid of the "1st Cup Fiera di Milano" race held in 1925. A race in 1925 with cars racing across the bridge. The Pista di Alta Velocità banking, 2003.

The first track was built from May to July 1922 by 3,500 workers, financed by the Milan Automobile Club[1] – which created the Società Incremento Automobilismo e Sport (SIAS) (English: Motoring and Sport Encouragement Company) to run the track.[2] The initial form was a 3.4 square kilometres (1.31 sq mi) site with 10 km (6.2 mi) of macadamised road – comprising a 4.5 km (2.8 mi) loop track, and a 5.5 km (3.4 mi) road track.[clarification needed][1][2] The track was officially opened on 3 September 1922, with the maiden race the second Italian Grand Prix held on 10 September 1922.[2]

In 1928, the most serious Italian racing accident to date[1][3] ended in the death of driver Emilio Materassi and 27 spectators at that year's Italian Grand Prix.[1][3] The accident led to further Grand Prix races' confinement to the high-speed loop until 1932.[4] For these reasons the Italian Grand Prix wasn't held again until 1931; in the meantime the 1930 Monza Grand Prix was held on the high speed ring only, while in 1930 Vincenzo Florio introduced the Florio Circuit. The 1933 Italian Grand Prix was held on the original complete layout but it was marred by the deaths of three drivers (Giuseppe Campari, Baconin Borzacchini and Stanisław Czaykowski) in the supporting Monza Grand Prix held on the same day - which became known as the "Black Day of Monza" - over the shorter oval circuit[2][5][6] and the Grand Prix layout was changed: in 1934 a short circuit with two lanes of the straight line joined by a hairpin, Curva Sud of the banking (with a double chicane) driven in the opposite direction than usual, the "Florio link" and the Curva Sud (with a small chicane). This configuration was considered too slow and in 1935 Florio Circuit was used again, this time with four temporary chicanes and another one permanent (along the Curva Sud of the banking). In 1938 only the last one was used.[7]

There was major rebuilding in 1938–39, constructing new stands and entrances, resurfacing the track, removing the high speed ring and adding two new bends on the southern part of the circuit.[2][4] The resulting layout gave a Grand Prix lap of 6.300 km (3.915 mi), in use until 1954.[8] The outbreak of World War II meant racing at the track was suspended until 1948[8] and parts of the circuit degraded due to the lack of maintenance and military use.[9] Monza was renovated over a period of two months at the beginning of 1948[2] and a Grand Prix was held on 17 October 1948.[8]

High speed oval

In 1954, work began to entirely revamp the circuit, resulting in a 5.750 km (3.573 mi) course, and a new 4.250 km (2.641 mi) high-speed oval with banked sopraelevata curves (the southern one was moved slightly north).[9][10] The two circuits could be combined to re-create the former 10 kilometres (6.214 mi)[9] long circuit, with cars running parallel on the main straight. The first Lesmo curve was modified to be made faster, and the track infrastructure and facilities were also updated and improved to better accommodate the teams and spectators.[2][10]

The Automobile Club of Italy held 500 mi (800 km) Race of Two Worlds exhibition competitions, intended to pit United States Auto Club IndyCars against European Formula One and sports cars.[9][10] The races were held on the oval at the end of June in 1957 and 1958,[11] with three 63 lap[12] 267.67 kilometres (166.32 mi) heat races each year, races which colloquially became known as the Monzanapolis series.[11][13] Concerns were raised among the European drivers that flat-out racing on the banking would be too dangerous,[13] so ultimately only Ecurie Ecosse and Maserati represented European racing at the first running.[14] The American teams had brought special Firestone tyres with them, reinforced to withstand high-speed running on the bumpy Monza surface, but the Maseratis' steering was badly affected by the larger-than-usual tyre size, leading to the Modena-based team withdrawal.[14]

Ecurie Ecosse's three Jaguar D-type sports cars used their Le Mans-specification tyres with no ill-effects, but since they raced at less than their practice speeds to conserve their tyres, they were completely outpaced. Two heats in 1957 were won by Jimmy Bryan in his Kuzma-Offenhauser Dean Van Lines Special,[14][15] and the last by Troy Ruttman in the Watson-Offenhauser John Zink Special.[16] In 1958 Jaguar, Ferrari and Maserati teams appeared alongside the Indy roadsters,[10][17] but once again the American cars dominated the event and Jim Rathmann won the three races in a Watson-Offenhauser car.[11]

Formula One used the 10 km (6.2 mi) high speed track in the 1955, 1956, 1960 and 1961 Grands Prix.[9][10] Stirling Moss and Phil Hill both won twice in this period, with Hill's win at Monza making him the first American to win a Formula One race. The combined circuit was not used for 3 years because during the 1956 event the Ferraris and Maseratis were suffering mechanically on the banking, and the combined circuit was used again in 1960 because Ferrari's main strength that year was straight-line speed and the organizers wanted to maximise this advantage.[18] The 1961 race saw the death of Wolfgang von Trips and fifteen spectators when a collision with Jim Clark's Lotus sent von Trips' car airborne and into the barriers at the approach to the Parabolica.[2][18]

Although the accident did not occur on the oval section of the track, the high speeds were deemed unsafe and F1 use of the oval was ended. Another attempt was made to use the combined circuit for the 1963 race, but the extremely bumpy nature and poor overall quality of the concrete banking saw some cars suffer mechanically. The teams protested and threatened to leave unless only the road circuit was used, which is ultimately what happened.[19] Future Grands Prix were held on the shorter road circuit,[10] with the banking appearing one last time in the film Grand Prix.[19] New safety walls, rails and fences were added before the next race and the refuelling area was moved further from the track. Chicanes were added before both bankings in 1966, and another fatality in the 1968 1000 km Monza race led to run-off areas added to the curves, with the track layout changing the next year to incorporate permanent chicanes before the banked curves – extending the track length by 100 m (110 yd).[10]

The combined circuit held its last major race in 1969 with the 1000 km of Monza, the event moving solely to the road circuit the next year; the banking has never been used again for any major races.[10] The banking still exists, albeit in a decayed state in the years since the last race, escaping demolition in the 1990s. It is used once a year for the Monza Rally, which served part of the 2021 World Rally Championship, which was the first FIA championship event since 1969.[19] The banked oval was used several times for record breaking until the late 1960s, although the severe bumping was a major suspension and tyre test for the production cars attempting endurance records, such as the Ford Corsair GT which in 1964 captured 13 records.[20]

Circuit changes and modernisation

Both car and Grand Prix motorcycle racing were regular attractions at Monza.[10] These races involved drivers constantly slipstreaming competing cars, which produced several close finishes, such as in 1967, 1969, and 1971.

As the speed of the machines increased, two chicanes were added in 1972 to reduce racing speeds – the Variante del Rettifilo at the middle of the start/finish straight,[21] and the Variante Ascari.[2] This resulted in a new circuit length of 5.755 km (3.576 mi).[21] Grand Prix motorcycles continued to use the un-slowed road track until two serious accidents resulted in five deaths, including Renzo Pasolini and Jarno Saarinen,[21] in 1973, and motorcycle racing did not return to Monza until 1981.[21] The 1972 chicanes were soon seen to be ineffective at slowing cars; the Vialone was remade in 1974,[21] the other, Curva Grande in 1976,[2] and a third also added in 1976 before the Lesmo, with extended run-off areas.[21] The Grand Prix lap after these alterations was increased to 5.800 km (3.604 mi) long.[21]

With technology still increasing vehicle speeds the track was modified again in 1979 with added safety measures such as new kerbs, extended run-off areas and tyre-barriers to improve safety for drivers off the track.[22] The infrastructure was also improved, with pits able to accommodate 46 cars, and an upgraded paddock and scrutineering facilities.[22] These changes encouraged world championship motorcycling to return in 1981, but further safety work was undertaken through the 1980s.[22] Also in the 1980s the podium, paddock and pits complex, stands,[22][23] and camp site were either rebuilt or improved.[2]

As motorsport became more safety conscious following the deaths of Ayrton Senna and Roland Ratzenberger in 1994 at the Imola circuit, the three main long curves were "squeezed" in order to install larger gravel traps, shortening the lap to 5.770 km (3.585 mi).[23] In 1997 the stands were reworked to expand capacity to 51,000.[23] In 2000, the chicane on the main straight was altered, changing from a double left-right chicane to a single right-left chicane in an attempt to reduce the frequent accidents at the starts due to the conformation of the braking area, although it is still deemed unsafe in terms of motorcycle racing. The second chicane was also re-profiled. In the Formula 1 Grand Prix of the same year, the first to use these new chicanes, a fire marshal, Paolo Gislimberti, was killed by flying debris after a big pileup at the second chicane.[3]

In 2007, the run-off area at the second chicane was changed from gravel to asphalt. The length of the track in its current configuration is 5.793 km (3.600 mi).[24] At the 2010 Monza Superbike World Championship round, Italian rider Max Biaggi set the fastest ever motorcycle lap of Monza when he rode his Aprilia RSV4 1000 F to pole position in a time of 1:42.121. In the Superpole qualification for the 2011 race, he improved on this lap time, for a new lap record of 1:41.745 and his speed was captured at 205+ mph.

In late 2016, work was planned on a new first bend, which would have bypassed the first chicane and the Curva Grande. Drivers were to go through a fast right hand kink and into a new, faster chicane. Work was planned for to be completed by 2017 in hopes of a renewed contract for Formula 1. Gravel would have also returned to the run-off area at the Parabolica bend.[25] However, plans for the track's change were suspended due to the track being in the historic Monza Park.[citation needed]