Anthony Joshua's next bout could take place in a Roman amphitheatre in Croatia, says the manager of mandatory challenger Kubrat Pulev.
Briton Joshua, 30, was meant to defend his IBF, WBA and WBO world heavyweight titles against Bulgaria's Pulev at Tottenham Hotspur Stadium on 20 June.
The fight was postponed because of the coronavirus pandemic and no alternative date or venue has since been set.
"We are discussing Croatia," said Pulev's manager Ivaylo Gotsev.
"There is a unique Roman stadium - Pula Arena - and we are in active talks."
Gotsev claims both camps have set aside four weeks to find a new venue if coronavirus measures in place in England do not change, with targets set to deliver the bout in August or September.
Boxing is currently shut down in the UK and the British Boxing Board of Control is preparing for bouts to return behind closed doors in July.
Joshua's promoter Eddie Hearn has said staging the world title bout behind closed doors was only going to be considered a "last resort".
And Gotsev believes the Croatia venue would allow fans to attend if the necessary safety measures were in place.
"We like this option because it is in Europe, in the middle of the continent," Gotsev added. "There will also be an opportunity for spectators with the right measures taken.
"There needs to be a mutual agreement. We want the terms and conditions to be beneficial for both parties. They can't meet in Bulgaria because Joshua will not agree."
Pula Arena has staged notable concerts featuring Foo Fighters, Luciano Pavarotti and Elton John.
Joshua was initially scheduled to fight Pulev at Cardiff's Principality Stadium in October 2017 but the 34-year-old Bulgarian, known as "The Cobra", withdrew after suffering a shoulder injury in sparring.
Pulev, one of Bulgaria's most popular sportsmen, suffered his only career defeat when he challenged for the IBF world heavyweight title in 2014, losing to Wladimir Klitschko in Hamburg on a fifth-round knockout.
His record stands at 28 wins from 29 bouts, while Joshua has 23 wins from 24.