A video compilation of old to new 4-member girl groups has surfaced on the net, which caused quite the stir among netizens.

The video shows the girl groups that debuted as early as 1998 until quite recently, including Fin.K.L, 2NE1, Brown Eyed Girls, Secret, & Sistar.

The video, which was put together by K-pop fans, is titled ‘The history of Korea’s 4-member girl groups’, and the 3-minute clip has become a huge hit on sites like Naver, Daum & Youtube, allowing netizens and fans alike to take a trip down memory lane.

Fans were able to listen to hit songs by their favorite groups, and it was quite visible how Korean music has evolved over the years. They were able to also take a look at the beginning stages of a few stars who are still very active in the entertainment industry today, such as Lee Hyori, Ock Ju Hyun, Sung Yuri, & Ryeowon.

Netizens responded to the video with, “I didn’t know there were so many 4-member girl groups!”, “Please make a video of 5-member girl groups, too!”, and “I can’t believe its been more than ten years since Fin.K.L debuted.”

Then why are groups with 4 members so popular? According to an entertainment insider, agencies tend to choose four-member groups so that each member can take on one of four roles: Visual, Dance, Vocal, and all around Entertainer.

Have a look at the video below!