I was surprised someone suggested TVXQ's Bolero! Even as an SM stan, since this song and performance is old, many people may not know about it. I haven't listened to it myself in so long. Bolero is one of their Japanese songs, and their Japanese songs is actually how I first knew about them. My grandma was a fan of theirs in Japan.
They were really popular in Japan, and together with BoA, the queen of kpop, they popularized kpop groups in Japan. Many people first think their songs are from Japanese artists in the beginning because they have really good pronunciations.
TVXQ even sang an opening song for one of the most popular anime One Piece called We Are which is a remake of the original opening.
