Boy band Bangtan Boys, also known as BTS, have been rewriting the history of K-pop, and their influence and popularity is truly global.

They have achieved so many milestones "in so little time" for a K-pop act -- one of them was two sold-out nights at Wembley Stadium in London in June last year.

They were the first Korean singers to perform at the iconic venue packed to its capacity of 60,000, following in the footsteps of legendary singers such as Queen, Michael Jackson, Madonna and Elton John.

But their beginning, like all the other greats, was humble. They debuted in 2013 with a showcase at a small performance hall in Seoul. The following year they held their first concert at the 2,000-seat Yes 24 Live Hall, attracting 6,000 people over three days. They could not hide their pure joy at seeing the large audience and said at the time that they "feel like real singers" overwhelmed by the fans' cheers.

BTS released a series of albums under the theme of "The Most Beautiful Moment in Life" in 2015, and had their second concert at the 3,000-capacity Olympic Hall in Seoul in March that year, and the third one at the 5,000-capacity SK Olympic Handball Gymnasium in Seoul in November, drawing over 15,000 fans in total for its three-day run.

BTS attributed their great success to their ardent fans. In fact, that could not be truer as the boys' fans, known as "the Army," have just kept growing globally and made a huge contribution to their phenomenal success.