People and cars jammed the infield of Indianapolis Motor Speedway in 1972, when an estimated 300,000 fans gathered to watch Mark Donahue win his one and only Indy 500. Donahue prevented Al Unser Sr., who started 19th but climbed to second, from becoming the first driver to win three straight races.

photograph by Heinz Kluetmeier

Thumbnails | Next Photo