The track's first event wasn't a car race
On June 5th, 1909, two months before the IMS's official completion, it served as a launch pad for a balloon race. The event drew 40,000 spectators, with the winner landing 382 miles away in Alabama. Presumably they mailed him his trophy.
The Indianapolis Motor Speedway is the highest-capacity sports venue in the world
The 2.5-mile oval boasts a seating capacity of approximately 250,000, plus infield accommodations that raise its head count to an unparalleled 400,000 (roughly the population of Cleveland). It's been No. 1 for a century and will likely keep its title unless someone installs bleachers onto the sides of the Grand Canyon.
It's also the hardest-to-leave sports facility in the world
It takes a long, long time to empty the place, which means the only cars moving quickly on race day will be the ones on the track. Savvy fans wait at least three hours until after the checkered flag drops before they go anywhere near their vehicles.