Epik High is one of the longest-running currently active groups in the Korean music scene, and this clip from 2007 shows them during what would become their most successful era to date. "Fan" was a single from their impressively-selling "Remapping the Human Soul" album, and told the story of an obsessive sasaeng fan's feelings for her idol. New viewers might find the long bangs and Hot Topic-inspired fashion surprising, but perhaps the greatest surprise of all is seeing Epik High doing choreography!

By 2007, Lee Hyori had already made a name for herself as one of the biggest Korean soloists of all time. Her every move was watched by the press and the fans alike, and her single "Toc Toc Toc" came out during a commercial peak which saw her acting. The sexy R&B/dance number caught the attention of fans, especially with Hyori donning a fabulous metallic purple outfit in its debut performance. That said, the song unfortunately became embroiled in one of her many controversies when it was used in her drama "If In Love...Like Them," which was banned from re-broadcast due to violations of product placement law.

Before Wonder Girls were a household name to K-pop fans, they were a fresh-faced debut from a then-building JYP Entertainment. Their debut song "Irony" is notable for featuring a contemporary R&B influence, unlike their subsequent throwback driven singles. Also worth noticing is the presence of a young Kim Hyun-ah, now known as HyunA, in the group prior to her departure.

Nell is a rock band that debuted in 2001, and their 2007 single "Good Night" was one of their many hits during the mid-2000s. This shows that the time period caught South Korea and the world at large during a period of diverse tastes, as rock music - and music with guitars in general - becomes more and more rare in the international music landscape.

As a group that came to prominence during the first generation of girl groups, Baby VOX worked hard to create a name for their selves. After gaining fame through a string of hip-hop, dance and electronic influenced singles, their label debuted sister group Baby VOX Re.V in 2007 with the single "Shee." The song is sexy and mature - so much so, in fact, that the choreography was deemed too sexual for broadcast and forced to change!

SS501 was one of the biggest boy groups of the 2000s, going head to head with Super Junior and TVXQ at their peak regularly. This song is the third single from their first album, and it finds them adopting a bright and friendly sound. Perhaps most notable here is their stage outfits, which featured bright colors, heavy bangs, and plenty of clashing patterns. Who else can't wait for that to be back in style?

Big Bang is a group that needs no introduction, though it's easy to forget that they had pretty humble beginnings. This performance finds the group baby-faced and energetic, with T.O.P kicking things off by rapping directly from the middle of the crowd. The remarkable stage outfits were full of clashing colors, crazy patterns, hip-hop influence, glasses without lenses, and even a backpack in Seungri's case. Though this song wasn't as popular as "Lies" before or "Haru Haru" after, it's certainly worth a reappraisal for the fashion alone.

Soloist Wax gained a lot of attention for this song in 2007, an anthem for those nights where you just end up drinking alone. The song became an anthem to the single and single-to-be, with its acoustic R&B style winning listeners over.

The 2000s were a great time to be a soloist in K-pop, and Ivy was no exception to this rule. Her single "Sonata of Temptation" came out to much fanfare in 2007, with its classical music-influenced sound helping to distinguish her from the competition. The performance features extravagant production and choreography, and truly captures the essence of 2000s excess.

Before she had her run on reality television with Crown J, Seo In Young was a member of the girl group Jewelry and even had a distinguished solo career of her own. "I Want You" found her exploring a hip-hop/R&B style, and though the sound was typical of the 2000s, the powerful choreography and catchy chorus helped her stand out from the crowd.