One Direction. BTS are no doubt great but you're forgetting there's this thing called streaming, a lot of what they get is because of their fans streaming their music all day all night until it reaches a certain count.

One direction, on the other hand, is not only the most popular band but also very raw in their art. Additionally, there is a fact about the band that EVERYONE is aware of. Probably because they make mostly English music. However, if you ask a random individual to name a BTS single or song, they will be unable to do so. No other band has been able to match or surpass One Direction's legacy, which is in a class of its own. In 2010, when boybands weren't hip, this band became the first to break every record set by the Beatles and to start a new age of boybands.

So yeah, One Direction made history. In a way, you could say that 1D is responsible for all of these boybands' current longevity. They simplified it and paved the path. Just THAT band, they are.