A capsule look at the Indianapolis 500, which will be run Sunday:
What: 99th running of "the greatest spectacle in racing."
When: Green flag about 12:15 p.m. ET
Where: Indianapolis Motor Speedway, Speedway, Ind., an Indianapolis suburb
Who: 33 drivers in open-wheel racers of the IndyCar circuit; field determined in qualifications
Defending champion: Ryan Hunter-Reay, United States
MORE: Images from 2014 race | Spectacular crashes | Indy's NASCAR drivers | Classic Indy photos | Past winners | Athletes we salute on Memorial Day
Rookie of the year: NASCAR's Kurt Busch won in 2014, finishing sixth. Fellow Sprint Cup driver AJ Allmendinger won in 2013, finishing seventh.
2015 field: 34 cars are entered. All use the Dallara chassis; 17 have Chevrolet engines, 17 have Honda engines. Teams break down as follows: Chevrolet teams: Penske 4, Ganassi 5, KVSH/KV 3, CFH 3, Dreyer & Reinbod/Kingdom 1, Lazier 1. Honda teams: Andretti 5, Coyne 3, Foyt 3, Schmidt 3, Rahal Letterman Lanigan 2, Herta 1.
TV coverage (all times ET; all via ABC unless otherwise noted): May 23, 5-6:30 p.m., 500 Festival Parade, NBC Sports Network; May 24, 11 a.m., 500 pre-race show; noon, Indianapolis 500 Mile Race
Past champions: List headed by four-time winners A.J. Foyt, Al Unser Sr. and Rick Mears. Complete list
Standards: Roger Penske has been owner for 15 Indy winners and 17 Indy pole winners. Dallara built the chassis for 10 winners. More winners (27) used Offenhauser engines. Arie Luyendyk holds the track speed record, 237.498 mph in 1996 while driving a Reynard/Ford-Cosworth XB.
Track: Indy is a relatively flat track with four turns, two short chutes and two long straightaways. The track itself is 2.5 miles. Nicknamed the Brickyard, IMS had been paved with brick before converting to its current asphalt surface. A yard-wide strip of brick remains at the finish line.
Did you know: Races have been scheduled for the Sunday before Memorial Day since 1974. IMS was built as a tar-and-gravel track in 1909. Races include NASCAR's annual Brickyard 400, motorcycle, Grand Prix, road racing and other motorsports. The first race included 40 cars; the field was pared to 33 in 1912. Races were not run in 1917-18 (World War I) and 1942-45 (World War II). European automakers entered the competition early, including Mercedes, Fiat and Peugeot. The race was known as the international sweepstakes race from 1911 through 2016. It was called the Liberty Sweepstakes in 1919. It is best known simply as the 500.
Personalities: Foyt turned 80 and had health issues the past year but returned to his familiar place on Gasoline Alley to greet fans and prepare his team.
Jeff Gordon, five-time winner of NASCAR's Brickyard 400, will drive the pace car. Gordon grew up in Pittsboro, Ind., and is retiring from full-time NASCAR racing this year. The pace car is a Chevrolet Corvette.
Nastia Liukin serves as grand marshal. A gold-medal gymnast at the 2008 Beijing Olympics, Liukin won her first senior U.S. all-around title at the U.S. Championships in Indy in 2005.
Florence Henderson, best known as the mother of The Brady Bunch, returns to sing "America the Beautiful" during May 24's prerace ceremony.
Jim Nabors will not sing the national anthem; he had done so from 1972-2014. Instead, Jordin Sparks, the 2007 "American Idol" winner, will sing the national anthem.
Perry Ferrell brought his band Jane's Addiction to May 22's Carb Day concerts. Also on the bill: classic rock band 38 Special and jam band O.A.R. On May 23, Florida Georgia Line performs. On race day, groups performing at the Snake Pit event will include Kaskade, Steve Aoiki, Atrak and Caked Up.