Zuffa's home base has always been Las Vegas, and there are usually a bunch of UFC shows in the city each year. In fact, most of their biggest PPV shows end up going down in Sin City. But the two major current arenas in the city that the UFC uses, located at MGM Grand and Mandalay Bay, have been around for a while and aren't exactly state-of-the-art. Because the city has no major sports franchises, the need for a new arena hasn't been high on anyone's to-do list.
MGM Sports International and AEG have broken ground on a new 375 million dollar arena that will have all the bells and whistles of an an arena that would host an NBA or NHL team. And according to UFC president Dana White, the UFC has been promised the first date at the venue even though Golden Boy CEO Richard Schaefer is willing to use top boxing draw Floyd Mayweather (who defeated Marcos Maidana last night) to be able to run the first show there. White jokingly dismissed Schaefer's claim, and said the new arena will mean that the UFC runs even more shows in the Vegas (via MMA Junkie):
"MGM already promised me the first date. I don’t care what Schaefer says."
"It will definitely open more dates for us. Plus, the one thing this town needed really bad was a state-of-the-art arena. … Whether it’s the Internet service or the production, all of these things are very important in putting on a world-class show, and it’s all going to change when this thing is built.
"It’s a game-changer for everybody – for the fans, for the people that are putting on the shows, and obviously for the city."
The arena isn't scheduled to open until 2016, and Mayweather may be retired by then. Either way, fans will probably be happy to attend an event in a more modern arena, which will hold 20,000 fans for UFC shows.