https://cdnph.upi.com/ph/st/th/6981781256849/2026/i/17812571166390/v1.5/BTS-to-launch-Busan-shows-for-Arirang-world-tour.jpg" /> K-pop supergroup BTS will begin the Busan leg of its "Arirang" world tour Friday, returning to the southern South Korean port city, alongside its global fan base, known as ARMY.