The 2010s featured the Chicago Cubs winning the World Series, the greatest comeback in Super Bowl history, 5,000-1 longshot Leicester City winning the Premier League and Tiger Woods returning from a career meltdown to capture the Masters.
The decade also saw the American sports betting landscape change forever.
On May 14, 2018, the United States Supreme Court struck down a federal statute that had restricted regulated sports betting to primarily Nevada for more than a quarter of a century. The landmark ruling sent dozens of states scrambling to get into the bookmaking business, and 20 states have currently authorized sports betting. It was a game-changer.
However, our most notable betting event of the decade didn't take place on the field or in the courtroom. It happened in 2017 inside the ring in Las Vegas between Floyd Mayweather and Conor McGregor, and it was a spectacle initially considered little more than a publicity stunt. It turned out to be the most heavily bet fight ever and an opportunity of a lifetime for professional gamblers.
Here is our look back at Mayweather-McGregor.
By the time the opening bell rang, late on that Saturday night in August at MGM Grand Garden in Las Vegas, more than $1 billion had likely been staked around the globe on a fight between a retired, undefeated boxing champion and a mixed martial arts star who had never boxed professionally.
In the final five hours leading up to the fight, nearly £12 million ($16.1 million) was traded on Mayweather-McGregor at Betfair, a prominent sports betting exchange in the United Kingdom. In total, a record £59 million ($79 million) was riding on the fight at Betfair, more than any other event in the company's history, including World Cup finals.
"It was so unique that we doubt we'll ever see anything similar betting-wise in a long time," Katie Baylis, spokesperson for Betfair, told ESPN in December.
In Nevada, the bulk of the small money backed the underdog McGregor. The day of the fight, bookmaking company William Hill U.S. said for every one bet placed on Mayweather, 19 came in on McGregor. The fight ended up attracting more than twice as much money and 50% more individual bets than Mayweather's 2015 bout with Manny Pacquiao, previously Nevada's most heavily bet fight. Mayweather-McGregor was the biggest decision in William Hill's history in the U.S.
Nevada Gaming Control officials estimated $65 million was bet on Mayweather-McGregor at the state's sportsbooks, including at least six $1 million wagers -- five more than reported for Super Bowl LI between the New England Patriots and Atlanta Falcons earlier in the year.
Rumors that the 40-year-old Mayweather (49-0) would come out of retirement to take on McGregor, a 29-year-old UFC champion, began surfacing more than six months in advance of the fight. It seemed outlandish and more of a cash grab for two polarizing personalities than an actual fight.
"Honestly, the first thing that came to mind was Thunderlips, Rocky against Hulk Hogan [in the movie "Rocky III"]," said Jay Rood, who at the time was the director of race and sports for MGM in Nevada.
Setting the odds, bookmakers said, was more about estimating the betting interest than gauging the fighters' skill sets. After all, they didn't have a lot to go on with McGregor's lack of boxing experience.
"You make a number based on what type of money and flow of money that you would expect at the counters," Jay Kornegay, vice president of race and sports at the Westgate in Las Vegas, said that summer. "It's not necessarily the true odds; it's just reflective of the betting patterns that we expect to see."
Some oddsmakers put Mayweather's true odds at -5,000 but knew there would be plenty of money on McGregor. The first prices appeared at Las Vegas sportsbooks in February, four months before the fight became official. Mayweather opened as a whopping -2,500 favorite (1-25), with McGregor a hefty 11-1 underdog.
While the books anticipated early money on McGregor, they far underestimated what was coming their way.
Forty of the first 42 bets on the fight at the SuperBook at Westgate Las Vegas were on McGregor. Most, but not all, bets on McGregor were small. However, MGM's sportsbook took two $100,000 wagers on the Irishman, and other books reported taking several five-figure bets on the underdog. The liability on McGregor (who was fetching 5-1 or greater odds) mounted quickly and reached unprecedented levels for a fight.
"The backing of an entire sport, UFC and MMA, was really surprising," said Rood, now chief risk officer at sports betting company Bet.Works. "Their fans showed up with their dollars, backing their belief that their guy was a superior fighter. The price was shocking, that it moved down so much and we took on so much liability."
Two months before the fight, MGM's liability on McGregor reached "significant seven figures."
"You never saw that," Rood said.
By June, when the fight became official, Mayweather's odds had dropped to -1,100 and McGregor 7-1. The price would continue to shrink. Professional bettors were salivating.
"[Floyd] is 49-0 for a reason, a perfect return on investment," Rood said at the time. "So I don't want to give too much away on that side and end up needing McGregor for a big amount. If you go back at Floyd's average price the last 10 years, it's got to be north of six dollars [-600], and that's against the top competition in boxing. So now you're going to give him a subaverage price for a guy that's never really boxed in his life. I'm not willing to put Floyd Mayweather on a blue-light special. We're at -750, and I think that's a blue-light special."
Apparently, Mayweather thought so, too.
Mayweather attempts to bet on himself
At approximately 3:30 p.m. PT -- a few hours before the fight -- Mayweather stopped in at the sportsbook at The M Resort in Henderson, Nevada, where he was a regular customer. However, he had never made a bet like the one he was trying to place the day of the fight.
Mayweather asked to bet $400,000 on his fight against McGregor ending under 9.5 rounds. The bookmakers were concerned over the legality of a fighter betting on anything other a straight win and told Mayweather to hold on, before they ultimately declined to take the bet.
"He was pissed," a source told ESPN the night of the fight.
Mayweather denied $400k bet on himself
Floyd Mayweather says he attempted to place a $400k bet on himself, but the casino wouldn't allow him to place the wager.
In 2017, neither the Nevada State Athletic Commission nor Nevada Gaming Control had specific regulations addressing a fighter's ability to bet on himself. Gaming Control has since tweaked a regulation that puts the onus on the state's sportsbooks to take "reasonable steps" to prevent anyone directly involved in an event from betting on that event.
"A book always has the option to say no, if they're unsure or not comfortable," said A.G. Burnett, chairman of Nevada Gaming Control Board at the time and now a partner at the law firm McDonald Carano. "Regardless of the amount of money wagered or the pressure a patron may place on a book or the amount of P.R., I don't think someone will fault the book for not taking the bet."
After the fight, Mayweather told ESPN that he gave a friend $400,000 to bet on under 9.5 rounds, but he said he was only able to get down $87,000.
Mayweather stopped McGregor 1 minute, 5 seconds into the 10th round. He would've won his attempted bet.
'The greatest bet ever'
Since Mayweather had always been a convincing favorite throughout his career -- -200 against Pacquiao, -300 versus Canelo Alvarez, -400 against Shane Mosely -- professional bettors couldn't believe they could get a similar price on Mayweather versus McGregor.
Mayweather's odds dipped under -400 in the days leading up the fight, and the big, smart money began appearing.
"I over-bet that fight," said Bill Krackomberger, a well-known professional sports bettor, who ended up getting more than $25,000 down on Mayweather. "I actually started doubting myself when the line started dropping, not even thinking that it's all these millennials, and all these kids who watch UFC. Their little $50, $100, $200 and $500 bets cumulatively added up to millions of dollars and forced the sportsbooks to over-move the lines to get the buyback from the sharps. I'm not sure there will ever be another betting opportunity like that again."
Shane Sigsbee of sports betting syndicate Imawhale Sports lives in the same Las Vegas neighborhood as Mayweather and has gotten to know the boxer in recent years. A few weeks prior to the McGregor fight, Mayweather asked Sigsbee if he was planning to bet on him. Sigsbee said of course and told Mayweather he was going to place the biggest bet of his life on him.
Mayweather, an avid sports bettor, often discussed betting strategies with Sigsbee but never got into specific dollar amounts. Sigsbee bet $50,000 to win $10,000 on Mayweather. His company has had more at risk on a game before, but this was the largest wager Sigsbee had ever made personally.
After the fight, Sigsbee got an invitation via text message to go over to Mayweather's house. With his betting slip in hand, Sigsbee jumped into his golf cart and drove a few streets over to Mayweather's place.
"Floyd came over to me and said, 'My man, my man, how much money did I make you tonight?'" Sigsbee recalled. "I said, 'Floyd, thank you so much' and showed him the ticket."
Mayweather couldn't believe it.
"The level of disappointment on his face was like [nothing] I'd ever seen," Sigsbee said with a chuckle. "He was disgusted that was how little I bet on the fight."
Despite Mayweather's disappointment, Sigsbee and other professional gamblers enjoyed one of the best betting opportunities they'd ever experienced. Bookmakers were so inundated with money on McGregor that they gladly accepted money on Mayweather, anything to help reduce their liability.
"It didn't matter," said Jason Simbal, who at the time of the fight was vice president of risk for Las Vegas sportsbook operator CG Technology. "There was not enough sharp money to bet Mayweather to hedge people's decisions. They had bet all their money already."
The fight started off with McGregor landing a couple clean shots and surprisingly staying very much in the fight through five rounds. Some bookmakers were sweating. The savvy Mayweather wore McGregor down late, though, and finished him off early in the 10th round when referee Robert Byrd stopped the fight, ending a remarkable betting event.
With two of the biggest fighters in their respective sports, six-figure bets on both sides and unprecedented line movement, it truly was an event we may never see again.
"It was a really unique opportunity," Sigsbee said. "Everyone thought it was the greatest bet ever."