The world heavyweight championship belts all reside in Britain since Deontay Wilder was beaten by Tyson Fury - so where is the next American threat coming from?
Wilder ended a barren spell for US boxing by winning the WBC belt in 2015.
But Anthony Joshua and Fury now hold every title on British shores meaning there is an opportunity for a US-based contender to make a name for themselves…
Last chance saloon
Adam Kownacki, the Pole whose entire career has been based on the east coast of America, saw his undefeated record unexpectedly go up in smoke at the hands of Robert Helenius last month. He was once considered a natural challenger to Wilder but must now rebuild after a bad knockout.
'Prince' Charles Martin looks best-placed to battle back into contention. The former IBF champion who lost his belt to Joshua is currently ranked at No 2 with that governing body, behind only Kubrat Pulev who will challenge next. Martin KO'd Gerald Washington for a career-best stoppage last time out.
Dominic Breazeale has lost both of his world title challenges, to Joshua and Wilder. His grudge match with Wilder ended inside one round.
Breazeale is next targeting Andy Ruiz Jr, with both needing a victory to rebuild their careers. He told Sky Sports about Ruiz Jr: "That's the fight that fans want to see, me and Andy Ruiz. I'd love to be able to get that rocking and rolling."
The forgotten men
Haiti-born Canada-based Bermane Stiverne won the vacant WBC title in 2014 in the fight that ended the Klitschkos' monopoly but lost his first defence to Wilder. Stiverne lost a rematch inside one round then, last year, was stopped by Britain's Joe Joyce. He hasn't fought since and, at 41, it may be the end of the road.
Former Navy man Gerald Washington's first defeat was a clubbing KO in his title challenge against Wilder, in a fight where he won a few early rounds. Since then he has lost inside the distance three more times.
Bryant Jennings was among the cast of American challengers outpointed by world champion Wladimir Klitschko. He was then knocked out by Luis Ortiz and, last year, lost both of his fights.
Big question marks
Andy Ruiz Jr has, of course, reached the mountain top in epic fashion by upsetting Joshua for the IBF, WBA and WBO titles last year only to lose an immediate rematch. The Mexican-American has plenty of questions to answer as a result - his fast combinations and experience make him a danger but his self-confessed lack of discipline is a worry. Only a brave man will want to find out what Ruiz Jr has left in the tank.
Jarrell 'Big Baby' Miller is a rare commodity in this list as an undefeated trash-talking American. He blotted his copybook by costing himself a scheduled challenge against Joshua in his home city, New York, by failing drug tests and hasn't returned since.
Miller said about facing Fury, with whom he shares Top Rank as a promoter: "I think that will be definitely in the future."
And he warned Wilder of his desire to be the new US No 1: "I would be on his chest all night, the exact same way [as Fury did], even worse."
Michael Hunter is the fastest-rising danger-man. The Matchroom-promoted Hunter is ranked in the top 10 of every governing body - his most alarming win was the stoppage of Martin Bakole and, most recently, he battled Alexander Povetkin to a draw.
He has, however, lost a cruiserweight title fight to Oleksandr Usyk. Like Usyk, Hunter must prove his size and strength in the biggest division.
"If I could choose to fight any of the top guys, it would be Fury," Hunter told Sky Sports. "I've already been in the ring with him as an amateur. I've got his number. I would stop him."
Hunter said about Joshua: "I don't think he should fight me [with the style that he used to beat Ruiz Jr]. He can't beat me at that game. The law is to fight the boxers, and box the fighters. One is the boxer, one is the fighter. I would be the boxer."
Trevor Bryan holds an interim version of the WBA belt and is unbeaten in 20 but hasn't boxed for nearly two years.
Colombia's Canada-based Oscar Rivas knocked down Dillian Whyte but lost that fight via decision, and hasn't boxed in the nine months since. He has signed with Top Rank and is fresh enough to re-establish the reputation as a dangerous threat that he came to Britain with.
Efe Ajagba, a Nigerian whose career is based in Texas, has won all 13 of his fights in the US. He is a powerhouse and still aged just 25 - last month he stopped Razvan Cojanu, a former world title challenger. The time must be approaching for a breakthrough performance from Ajagba.
The next generation
Cuban Frank Sanchez Faure has racked up 15 wins in America and his co-manager Mike Borao told Sky Sports: "Frank would consider a fight against one of UK's big names immediately, especially Anthony Joshua.
"He will quickly advance past other prospects in the US and UK because of his incredible amateur pedigree, combination of speed, power, and an unmatched desire to win."
Jermaine Franklin has won all 20 of his fights and told Sky Sports: "It's a little hard to get your shot, because of the people that you need to get your shot with. They just don't want to take the risk right now."
Franklin's manager Dmitriy Salita added: "Jermaine has the skills and heart of a champion and at some point would love to make a meaningful UK debut."
Darmani Rock is another young prospect with a KO résumé and an undefeated 17-fight record.
Two big threats are also emerging in Canada - Simon 'The Grizzly' Kean is older at 31 and responded to his only defeat with four knockout wins in a row, while 'Monster Mel' Mladen Miljas has won all 12 of his fights inside the distance.