By 1975, race fans had known for decades what a special and hallowed place the Indianapolis Motor Speedway was. That year, the U.S. government made it official.
On race day, May 25, 66 years after it opened, the Indianapolis Motor Speedway was added to the National Register of Historic Places.
For the 59th 500, six previous winners were in the field of 33 looking to make history again, including three in the front row, AJ Foyt, Gordon Johncock and Bobby Unser.
But before a winner made his way into victory circle, fire and rain would make the day memorable.
Lap 126, Tom Sneva, in just his second race, came off the second turn, went airborne, hit the wall and caught fire. Amazingly, he survived with just a few minor burns.
Late in the race, Bobby Unser and Johnny Rutherford were battling it out when, out of nowhere, the heavens opened in a huge downpour.
The yellow came out, but the race wasn't red flagged immediately. The cars sent up rooster tails as the drivers tried to carefully make their way around, some more successfully than others.
The red and checkered flags came out together after 174 laps. The front straightaway barely visible, mother nature sealed Bobby Unser's fate, who was in the lead when the deluge hit.
He crept his way across the finish line for the second 500 win of his career.