Seoul is transforming itself into an extended concert venue ahead of BTS' comeback show Saturday, with the city government rolling out a month of landmark lighting, themed festivals and guided tours designed to give the hundreds of thousands of fans — collectively known as ARMY — more than a single night out, the Seoul Metropolitan Government announced Monday. Starting Friday, the day the highly anticipated album "Arirang" drops, 15 city landmarks, including Sebitseom and Cheonggye Stream, will be lit in purple — the color associated with the band — to mark their return, turning its skyline into a dynamic nighttime stage. City officials say the lighting is designed to make Seoul feel like a giant open-air performance space. To demonstrate the city’s welcome, greeting banners will be hung along Sejong-daero near the Gwanghwamun concert venue and “welcome ARMY” messages will be displayed on 10 media facades across the city. Major tourist spots and traditional marketplaces will also show welcome phrases in seven languages — English, Chinese, Japanese, Vietnamese, Indonesia