On December 14, 1909, four months after tragedy struck at the Indianapolis Motor Speedway, race car drivers test out its newly resurfaced—and presumably safer—track. Workers had just finished laying down 3.2 million 10-pound brick pavers over the 2.5-mile oval, which had previously been covered in a messy and dangerous mix of crushed limestone, gravel and tar.

The distinctive "Indy brickyard" surface remained until 1961, when almost all the pavers were buried under asphalt. One yard of the original bricks remain exposed at the start-finish line; kissing them after a successful race remains a tradition among Indy drivers.

In 1908, the auto-headlight mogul and race promoter Carl Fisher decided to build a five-mile track that would give carmakers a safe place to test and show off their vehicles. He signed up three partners and bought 320 acres of farmland on the edge of Indianapolis, across the street from his Prest-O-Lite headlight factory. The original plans for Fisher’s “motor parkway” called for a three-mile “outer” loop and a two-mile course through the infield. But they were hastily redrawn when someone pointed out that such a long track would not fit on the parcel unless all the grandstands along the straightaways were eliminated. As a compromise, Fisher and his construction superintendent decided to build a 2.5-mile banked oval with grandstands on all sides.

Instead of the concrete surface that other racecourse builders were using, Fisher covered his track with a sticky amalgam of gravel, limestone, tar and 220,000 gallons of asphaltum oil. For months, 500 workers and 300 mules laid layer after layer of the gooey mixture on the Indy loop and pulled steamrollers across it, pressing the roadway into a solid mass.

In August 1909, the Indy speedway was ready to open. The first race at the new Motor Speedway, a motorcycle race on August 13, was a disaster: The new track was so abrasive that it popped everyone’s tires, and workers had to take a few days to sand it down before the event could continue. Even after that, the track was still a mess: As race car teams arrived at the speedway a week later to prepare for the 300-mile Wheeler-Schibler race, one historian reported, “drivers were quickly covered with dirt, oil, and tar…the track surface disintegrated in the turns, [and] flying gravel shattered goggles and bloodied cheeks. Driving at Indy was like flying through a meteor shower.”

On the first day of that first car race, driver Wilford Bacuque and his mechanic were killed when their Knox flipped over and bounced into a fence post. Then, three more people died when driver Charlie Merz shredded a tire and went flying into the stands. After AAA threatened a boycott, Fisher agreed to suspend all races at the Indy track until he could put down a safer surface.

He decided on bricks because traction tests confirmed that they were less slippery than gravel and sturdier than concrete. When the “Brickyard” opened, it was much less dangerous than it had been, and only seven people were killed there between 1909 and 1919. The speedway kept its brick track for nearly 50 years. Today, the speedway has an asphalt surface.