Authorities in Seoul are preparing extensive security and traffic measures ahead of the BTS comeback concert set for March 21 at Gwanghwamun Square. Here’s what visitors should know. Entry Access to the viewing area will be limited to 31 designated gates around the square and nearby Sejong-daero. Security Metal detectors will be installed at all gates and bag checks will begin at 7 a.m. Authorities are asking visitors to bring minimal belongings. Police will also deploy CCTV monitoring teams and