KEY POINTS:
The Indy 500 winner has drunk a bottle of milk after the race since 1936 champ Louis Meyer downed a bottle after his victory.
He told reporters that his mother had recommended buttermilk to refresh him after the race.
Someone at the US Milk Foundation got on the bandwagon and ensured that every winner got a bottle of milk after the race - and it stuck.
Orange farm owner Emerson Fittipaldi broke with tradition though, drinking orange juice after one of his victories.
PETA - People for the Ethical Treatment of Animals - once called for the practice to be banned as it was cruel to calves and racist, as African-Americans had an enzyme which made milk difficult to digest.
Other traditions include calling the pit area Gasoline Alley, although petrol hasn't been used to run IndyCars for decades - they use ethanol.
There is a row of bricks across the start-finish line which mark the Indianapolis Motor Speedway's earliest beginnings as a brick yard.
The very first pace-car controlled rolling start is thought to have come from the first Indy 500 in 1911.
There are 33 cars in an Indy 500, lined up three abreast. In The first two races, in 1911 and 1912, had 40 and 24 entries, respectively, but they were lined up in rows of five.
From 1913 to 1920, the cars were lined up four abreast, then for safety reasons, the traditional three-abreast lineup began in 1921.