SEOUL — BTS is back, and the K-pop boy band’s fans have taken over the city.

Seoul’s landmarks were lit red, the signature color of the band’s new album. Restaurants and shops decorated their storefronts purple, the color associated with its fandom. Coffee shops and cocktail bars emblazoned their drinks with the logo of the band’s new album. Fans cheered as a drone show displaying the seven band members’ faces lit up the sky over the Han River.