LAS VEGAS - The fight most believed was nothing more than an impossible fantasy is happening.
The undefeated all-time pound-for-pound great Floyd Mayweather, he of 12 world titles in five weight classes, will exit a two-year retirement for one fight to face UFC star Conor McGregor, who is crossing over to boxing from MMA for a fight that was initially just a germ in his mind when he brought up the possibility in a 2015 television interview.
Two years later, huge amounts of social media fervor, genuine demand from combat sports fans intrigued by a pairing of these two huge personalities, a boatload of money, and a wild four-city media tour .