LOUISVILLE, Ky. — What does the 149th running of the Kentucky Derby hold? A celebration of the 50th anniversary of the start of Secretariat’s record-setting Triple Crown feat, sure. But, after years of spectacles, drama is also a sure bet.

In 2019, a year after Justify became only the 13th Triple Crown winner, many observers expected a quiet Derby. But then Maximum Security was disqualified for interfering with other horses after a tense review period that lasted nearly 22 minutes. In the end, the victory was handed to the 65-1 shot Country House. In the 145-year history of the Derby, no other horse had lost a win for such an act.

In 2020, the coronavirus pandemic kept fans far from the glow of the Twin Spires on the first Saturday in May. When Authentic pulled off a gate-to-wire victory, giving Bob Baffert his record-tying sixth Derby champion, the horse did so without the guttural roar that usually cascades down from the 150,000-capacity grandstand. There were no broken Derby glasses, no all-night victory parties, only protests for racial justice and a few stragglers in camping chairs outside the gates.

A diminished but festive crowd returned in 2021, and Medina Spirit, a 12-1 shot trained by Baffert, crossed the finish line first. Baffert notched his seventh Derby victory, surpassing the record set by Ben Jones, and the party was back on — until it wasn’t. Medina Spirit failed a drug test after the race and was disqualified months later, handing the victory to the 26-1 shot Mandaloun. Baffert was banned from the Derby for two years.

Desperate for a feel-good story, hard-core horseplayers and casual fans alike got one in 2022 when the 80-1 long shot Rich Strike, who was not even in the field until Friday, came from behind to pull off one of the biggest shocks in Derby history.

Before this year’s race was even run, Lord Miles, trained by Saffie Joseph Jr., was scratched by stewards after two of Joseph’s horses collapsed and died at Churchill Downs. Two other horses, not trained by Joseph, also died after sustaining leg injuries, including a colt who was also scheduled to run in the Derby, prompting an investigation by the Kentucky Horse Racing Commission into the causes of all the deaths. Four other horses were scratched, including the favorite, Forte, who stumbled during training on Thursday morning.

Japan has its best shot yet to make America’s greatest dirt race the world’s greatest.

Many are expecting big things out of the horses that have shipped from Japan, especially after horses from there won multimillion-dollar races at the Breeders’ Cup and Royal Ascot and in the Middle East. Japanese horses won this year’s Dubai World Cup and Saudi Cup.

The best of them is Derma Sotogake, who will break from the No. 17 post at odds of 10-1. He is trained by Hidetaka Otonashi and will be ridden in the Derby by the Frenchman Christophe Lemaire. Lemaire gunned Derma Sotogake to the front and never looked back in winning the U.A.E. Derby in Dubai, where Japan took the top four spots. But Lemaire says the colt does not need the lead.

“In the past, he has won from the middle and from the front,” Lemaire said. “He can adapt to the conditions of the race, and that is a big advantage for me.”

Still, the colt has much to overcome. Horses coming from the U.A.E. Derby are 0 for 18 in the Derby and have never even hit the board. The best finish came from Master of Hounds, who was fifth in 2011.

A more intriguing choice from Japan is Mandarin Hero (20-1), who ran last month in the Santa Anita Derby and came a neck short of upsetting Practical Move, a serious Derby contender before he was scratched. Mandarin Hero’s trainer, Terunobu Fujita, decided to cancel their return flight to Japan in hopes of getting a Derby starting spot even though his colt did not have enough points to qualify.

Mandarin Hero drew in after the late scratches, which included another Japan-based horse, Continuar. Mandarin Hero has looked fresh in the mornings here, and the Canada-based Kazushi Kimura rode him at Santa Anita and will be back on board for the Derby.

The Churchill Downs paddock area is blanketed by asphalt, and there are other big changes afoot.

In the shadow of the Twin Spires lies one of the most cherished features of Churchill Downs: the saddling paddock. And this year it’s a construction site.

The area is undergoing a $200 million renovation — and it’s only halfway complete. But the race must go on, so crews have erected temporary stalls and laid down wood chips on the walking ring and artificial turf in the middle. The rest of the massive 138,000-square-foot space has been blanketed with asphalt, giving it the look of an oval spaceship that has landed in the heart of the racetrack.

“They’ve made it so you can see more and be part of the process,” said Chris Riley, a Louisville native who now lives in Atlanta and has been to more than 40 Derbies. “But next year will be when we can judge it.”

When the project is complete, for the 150th Derby, it will offer terraced standing-room viewing, premium seating, club spaces and even dining options. Twenty-one saddling stalls will flank the tunnel connecting the paddock to the racetrack. The statues of Aristides, the first Derby winner, and the jockey Pat Day, the track’s all-time leader in every major category, have been moved elsewhere and will return to the paddock area when the construction is finished. The tradition of hanging a sign above the previous winner’s stall will continue as well, even with the temporary setup.

Eustace Fernandes, who has lived in Louisville since 1993, has been to at least 20 Derbies. Last year, he met Brenda Brown of Frisco, Texas, and Sheri Hightower of Denver, both longtime flight attendants, on the rail at the paddock. They have texted nearly every week ever since and were back there Friday.

“She never knew she had seats until Eustace told her,” Hightower said of Brown. “We’re always at the paddock.”

The vantage point — “the best in the house,” Fernandes said — is what they like about the new configuration. “It’s a great view of the horses, which is what the three of us love,” Hightower said.

And it’s not just the paddock that has a new look. A $90 million first turn project, essentially a three-story structure reminiscent of what you’d find at a soccer stadium, is being unveiled. It replaces a temporary seating area around the first turn and adds thousands of indoor and covered seats as well as a dining area.