AKB48 is a massive all-female Japanese idol group that's basically defined the modern idol industry. They've got around 120 members split across five teams—Team A, Team K, Team B, Team 4, and the Toyota-backed Team 8—plus a rotating roster of trainees called Kenkyusei who fill in when needed. Each team runs somewhere between 12 and 18 members.

What sets them apart from basically every other idol group in Japan is that they're theater-based. They've got their own dedicated theater on the 8th floor of a Don Quixote building in Akihabara, Tokyo, where they perform constantly—literally every weekday once, plus twice on weekends. It's kind of their whole thing.

The numbers behind AKB48 are honestly ridiculous. They've released 49 singles and nearly all of them have crossed the million-copy mark. By June 2017, they'd racked up 50 million single sales and over 6 million album sales combined. They were the first female group ever to win Japan's prestigious Record Award, which they grabbed in 2011 for "Flying Get." On top of that, they became the first artist period to sweep four major categories at the Billboard Japan Awards—best artist, top pop act, best single of the year, and best single sales of the year.