After debuting in 2013 with their single album 2 Cool 4 Skool, BTS released their first Korean-language studio album, Dark \u0026 Wild, and Japanese-language studio album, Wake Up, in 2014. The group's second Korean studio album, Wings, was their first to sell one million copies in South Korea. By 2017, BTS crossed into the global music market, leading the Korean Wave into the United States and breaking numerous sales records.