The bourbon will flow again, flowery hats and humans will return to the scene and 19 horses will run the most chaotic race of their lives. After being disrupted by a pandemic, the Kentucky Derby is back with many of its traditions intact.America’s longest continuously held sporting event returns to its traditional spot on the calendar — the first Saturday in May. The 147th edition comes less than eight months after its run without spectators last September because of COVID-19, making it the shortest time between Derbies in history. Here, we'll break down everything you need to know about the biggest event in Louisville:The horsesEach year, 20 horses compete in the Kentucky Derby. Essential Quality is the early 2-1 favorite on Saturday and has the bona fides. The striking gray colt was last year's 2-year-old champion. He comes in undefeated in five career starts. The last unbeaten colt to win the Derby was Justify in 2018, and he went on to sweep the Triple Crown.Essential Quality's jockey, Luis Saez, is seeking his first Derby win after crossing the finish line first aboard Maximum Security in 2019 only to have his colt disqualified.“Essential Quality is a deserving favorite,” trainer Todd Pletcher said, “but I think it's a wide-open race.”Besides Essential Quality, the other undefeated horses in the field are 5-1 Rock Your World and 50-1 Helium, both 3-0. Rock Your World won his first two starts on turf before switching to dirt and winning the Santa Anita Derby.→ Current leaderboard→ Horse study guideAs of Friday afternoon, one horse has scratched: King Fury, leaving only 19 for Saturday's race. Click here for a look at all the remaining horses.Make your betNow that you know the horses, time to make your bet. If you're going, you can bet at Churchill Downs. You can also place bets online, by clicking here.Not sure what you're doing? This page includes expert tips and a betting calculator. Changes due to COVID-19Attendance of about 45,000 is expected at the Derby, about 100,000 less than usual.Churchill Downs limited seating to 40-50%, up to 60% in certain private areas that allow social distancing.Churchill Downs officials anticipate about 50,000 people for Oaks and Derby.Masks will be mandatory — which should come as no surprise with a statewide mandate still in place.Churchill Downs says it has implemented a "Compliance Ambassador program" to drive awareness and adoption of public safety measures. Signage is placed throughout the facility, including the Infield, to remind guests to wear masks and practice social distancing.In addition, food and drinks are all-inclusive to lessen long lines and separate payments for every transaction. The fashionHalf the fun of the Derby is the fashion, of course! And with fans back in the stands, there is sure to be plenty of it.The Associated Press contributed to this report.