Downtown Seoul buzzed with a festive mood Saturday as fans gathered for K-pop group BTS' comeback concert, with some singing the Korean folk song "Arirang" -- the name of the septet's new album. Throngs of people had already gathered at Gwanghwamun Square in the morning ahead of the group's long-awaited return to the stage after a four-year hiatus caused by the members completing mandatory military service. Fans were elated about the group's return with its fifth studio album "Arirang" on Friday