Highlights from the ninth running of the Indianapolis 500

RACE: Ninth Indianapolis 500

DATE: May 30, 1921

WINNER: Tommy Milton, Louis Chevrolet

AVERAGE SPEED: 88.621 mph

WHAT HAPPENED: American driver Tommy Milton won the first of his two Indy 500s, taking advantage of a mechanical breakdown in Ralph DePalma's car midway through the race. DePalma would retire afterward with one victory and 612 laps led, a record that would stand until Al Unser Sr. tied it in 1987.

NOTABLE: For the first time, cars lined up in rows of three, creating the now-familiar Indy 500 starting grid. But whereas the modern race includes 33 entries, there were just 23 for the 1921 running. Eight of them would complete the 200-lap race with Americans sweeping the top five spots.