The Indianapolis 500-Mile Race, also known as the Indianapolis 500, the 500 Miles at Indianapolis, the Indy 500 or The 500, is an American automobile race, held annually, typically on the last weekend in May (specifically over the Memorial Day weekend) at the Indianapolis Motor Speedway in Speedway, Indiana. The event lends its name to the IndyCar class, or formula, of open-wheel race cars that have competed in it. The event, billed as The Greatest Spectacle in Racing, is considered one of the three most significant motorsports events in the world. The official attendance is not disclosed by Speedway management, but the permanent seating capacity is more than 257,000 people, and infield seating raises capacity to an approximate 400,000. The Indianapolis Motor Speedway complex was built in 1909 as a gravel-and-tar track and hosted a smattering of small events, including ones for motorcycles. The first long distance event, in "fearful conditions", was the 100-lap Prest-O-Lite Trophy in 1909, won by Bob Burman in a Buick. Breakup of the asphalt led to two fatal accidents in the first two long-distance events (a 250　mi (400　km) and 300　mi (480　km), which was shortened to 235　mi (378　km) after two severe wrecks). That these spectacles had attracted 15,000 paying customers (and crowds of up to 40,000) persuaded principal owner Carl G. Fisher to spend US$155,000 on repaving the track with 3.2 million bricks; he also added a 2　ft　9　in (0.84　m) concrete wall around the track's circumference. During the 1910 Memorial Day weekend, the first events on the newly-paved circuit drew 60,000 spectators; Ray Harroun won the 200　mi (320　km) Wheeler-Schebler Trophy in a Marmon. The crowds grew progressively smaller for the rest of the season, however, so the track owners chose to focus on a single race. They considered a 24-hour contest, in the fashion of Le Mans, or a 1,000　mi (1,600　km). They instead chose a 500　mi (800　km) contest, and offered a specatular $US25,000 purse. The combination allowed the track to rapidly acquire a privileged status for automobile races. The first "500" was held at the Speedway on Memorial Day, May 30, 1911, run to a 600　cu　in (9,800　cc) maximum engine size formula. It saw a field of 40 starters, with Harroun piloting a Marmon Model 32-based Wasp racer — outfitted with his invention, the rear view mirror. Harroun (with relief from Cyrus Patschke) was declared the winner, although Ralph Mulford protested the official result. 80,000 spectators were in attendance, and an annual tradition had been established. Many considered Harroun to be a hazard during the race, as he was the only driver in the race driving without a riding mechanic, who checked the oil pressure and let the driver know when traffic was coming. In 1912, the purse was raised to US$50,000. The field was limited to 33 (where it remains) and a riding mechanic was made mandatory. This second event was won by Joe Dawson in a National, after Ralph de Palma's Mercedes broke. Although the first race was won by an American driver at the wheel of an American car, European makers such as the Italian Fiat or French Peugeot companies soon developed their own vehicles to try to win the event, which they did from 1912 to 1919. The 1913 event saw a change to a 450　cu　in (7,400　cc) maximum engine size. After World War I, the native drivers and manufacturers regained their dominance of the race. Engineer Harry Miller set himself up as the most competitive of the post-war builders. His technical developments allowed him to be indirectly connected to a history of success that would last into the mid-1970s. In 1946 American operatic tenor and car enthusiast James Melton started the tradition of singing "(Back Home Again in) Indiana" before the race when asked to do so on the spur of the moment by Speedway president Tony Hulman. This continued through the years, notably by actor and singer Jim Nabors since 1972. Following European trends, engine size was limited to 183　cu　in (3,000　cc) during 1920-2, 122　cu　in (2,000　cc) for 1923-5, and 91　cu　in (1,490　cc) in 1926-9.[28] The 1920 race was won by Gaston Chevrolet in a Frontenac, prepared by his brothers, powered by the first eight-cylinder engine to win the 500. For 1923, riding mechanics were no longer required. A supercharged car, ID, first won the race in 1924. In 1925, Pete DePaolo was the first to win at an average over 100　mph (160　km/h), with a speed of 101.13　mph (162.75　km/h). In the early 1920s, Miller built his own 3.0 litre (183 in³) engine, inspired by the Peugeot Grand Prix engine which had been serviced in his shop by Fred Offenhauser in 1914, installing it in Jimmy Murphy's Duesenberg and allowing him to win the 1922 edition of the race. Miller then created his own automobiles, which shared the 'Miller' designation, which, in turn, were powered by supercharged versions of his 2.0 and 1.5 liter (122 and 91 in³) engine single-seaters, winning four more races for the engine up to 1929 (two of them, 1926 and 1928, in Miller chassis). The engines powered another seven winners until 1938 (two of them, 1930 and 1932, in Miller chassis), then ran at first with stock-type motors before later being adjusted to the international 3.0 liter formula. After purchacing the Speedway in 1927, Eddie Rickenbacker prohibited supercharging and increased the displacement limit to 366　cu　in (6,000　cc), while also re-introducing the riding mechanic. In 1935, Miller's former employees, Fred Offenhauser and Leo Goosen, had already achieved their first win with the soon-to-become famous 4-cylinder Offenhauser or "Offy" engine. This motor was forever connected with the Brickyard's history with a to-date record total of 27 wins, in both naturally-aspirated and supercharged form, and winning a likewise record-holding 18 consecutive years between 1947 and 1964. In the meantime, European manufacturers, gone from the Indianapolis 500 for nearly two decades, made a brief return just before World War II, with the competitive Maserati 8CM allowing Wilbur Shaw to become the first driver to win consecutively at Indianapolis in 1941. With the 500 having been a part of the Formula One World Drivers' Championship between 1950 and 1960, Ferrari made a discreet appearance at the 1952 event with Alberto Ascari, but European entries were few and far between during those days. In fact, it was not until the Indianapolis 500 was removed from the Formula One calendar that European entries made their return, with Australian Jack Brabham driving his slightly modified F1 Cooper in the 1961 race. In 1963, technical innovator Colin Chapman brought his Team Lotus to Indianapolis for the first time, attracted by the large monetary prizes, far bigger than the usual at a European event. Racing a mid-engined car, Scotsman Jim Clark was second in his first attempt in 1963, dominating in 1964 until suffering suspension failure on lap 47, and completely dominating the race in 1965, a victory which also interrupted the success of the Offy, and offering the 4.2 litre Ford V8 its first success at the race. The following year, 1966, saw another British win, this time Graham Hill in a Lola-Ford. Offenhauser too would join forces with a European maker, McLaren, obtaining three wins for the chassis, one with the Penske team in 1972 with driver Mark Donohue, and two for the McLaren works team in 1974 and 1976 with Johnny Rutherford. This was also the last time the Offy would win a race, its competitiveness steadily decreasing until its final appearance in 1983. American drivers kept on filling the majority of entries at the Brickyard for the following years, but European technology had taken over. Starting in 1978, most chassis and engines were European, with the only American-based chassis to win during the CART era being the Wildcat and Galmer (which was actually built in Bicester, England) in 1982 and 1992 respectively. Ford and Chevrolet engines were built in the UK by Cosworth and Ilmor, respectively. After foreign cars became the norm, foreign drivers started showing up at the Indianapolis 500 on a regular basis, choosing the United States as their primary base for their motor racing activities. Brazilian Emerson Fittipaldi, Italian Teo Fabi and Colombian Roberto Guerrero, were able to obtain good outings in the 80s, as did Dutchman Arie Luyendyk. However, it wasn't until 1993 that reigning Formula One World Champion Nigel Mansell shocked the racing world by moving to the United States, winning the CART PPG IndyCar World Series Championship and only losing the 500 in his rookie year because of inexperience with green-flag restarts. Foreign-born drivers became a regular fixture of Indianapolis in the years to follow. Despite the increase in foreign drivers commonly being associated with the CART era, it should be noted that four of the first six Indianapolis 500 winners were non-US drivers. The race was originally advertised as the "International 500-Mile Sweepstakes Race" from 1911–1916. However, from the start the race was known as the Indianapolis 500 or, more simply as the "500." In 1919, the race was referred to as the "Liberty Sweepstakes" following WWI. From 1920–1980, the race reverted to the "International Sweepstakes" name, or slight variations such as "International Sweepstakes Race, Distance 500 Miles." Following WWII, the race was commonly recognized as "The 500", "The 500-Mile Race", "Indianapolis 500-Mile Race", "Indianapolis 500," or "Indy 500," and usually the ordinal (e.g. "50th") preceded it. Often the race was also advertised on the radio as the "Annual Memorial Day race," or similar variations. For the 1981 race, the name "65th Indianapolis 500-Mile Race" was officially adopted, with all references as the "International Sweepstakes" dropped. Since 1981, the race has been advertised in this fashion, complete with a unique annual logo and the ordinal always included. Around that same time, in the wake of the 1979 race entry controversy, and the formation of CART, the race changed to an invitational event, rather than an Open, rendering the "sweepstakes" description invalid. The Borg-Warner Trophy, introduced in 1936, proclaims the event as the "Indianapolis 500-Mile Race," with no reference at all to the name "International Sweepstakes." In 2009, the Indianapolis Motor Speedway began a three-year long "Centennial Era" to celebrate the 100th anniversary of the opening of the track (1909), and the 100th anniversary of the first Indy 500 (1911). As a gesture to the nostalgic Centennial Era celebration (2009–2011), tickets for the 2009 race donned the moniker "93rd 500 Mile International Sweepstakes." It is the first time since 1980 that the "Sweepstakes" title has been used. During the month of May 2009, the ordinal (93rd) was used very sparingly, and for the first time since 1981, was not identified on the annual logo. Instead, in most instances in print, television, and radio, the race was referred to as the "2009 Indianapolis 500." Since the race was not held during WWI and WWII, the advertised Centennial Era will occur during the 93rd/94th/95th runnings. To avoid confusion between the 100th anniversary, and the actual number of times the race has been run, references to the ordinal during the Centennial Era are being curtailed.