Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Race | Circuit | Date | Pole position | Winning driver | Constructor | Tyre | Report |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Argentine Grand Prix | Buenos Aires | 17 January | Giuseppe Farina | Juan Manuel Fangio | Maserati | P | Report |
| Indianapolis 500 | Indianapolis | 31 May | Jack McGrath | Bill Vukovich | Kurtis Kraft - Offenhauser | F | Report |
| Belgian Grand Prix | Spa-Francorchamps | 20 June | Juan Manuel Fangio | Juan Manuel Fangio | Maserati | P | Report |
| French Grand Prix | Reims | 4 July | Juan Manuel Fangio | Juan Manuel Fangio | Mercedes | C | Report |
| British Grand Prix | Silverstone | 17 July | Juan Manuel Fangio | José Froilán González | Ferrari | P | Report |
| German Grand Prix (a.k.a European Grand Prix ) | Nürburgring | 1 August | Juan Manuel Fangio | Juan Manuel Fangio | Mercedes | C | Report |
| Swiss Grand Prix | Bremgarten | 22 August | José Froilán González | Juan Manuel Fangio | Mercedes | C | Report |
| Italian Grand Prix | Monza | 5 September | Juan Manuel Fangio | Juan Manuel Fangio | Mercedes | C | Report |
| Spanish Grand Prix | Pedralbes | 24 October | Alberto Ascari | Mike Hawthorn | Ferrari | P | Report |
Question:
What was the date of the Circuit of Indianapolis?
Answer:
31 May