Their first appearance, on a Korean pop music television show in February of 2007, was followed by the mini-album The Wonder Begins (which was released a few days later). Before the Wonder Girls could get rolling on their debut album, however, a series of events occurred that threatened to derail them. First, Ahn So Hee was injured in an accident during a video shoot, then Kim Hyun A was pulled from the group by her parents out of concern for her health -- she was later replaced by Kim Yoo Bin. Finally, the entire band was injured in a van accident while returning from a gig.

In September of 2007, the group was finally able to release that debut full-length, The Wonder Years. The lead single, "Tell Me," was a hit, and the group made appearances in China and the United States. An EP featuring remixes and new tracks titled The Wonder Years: Trilogy arrived in 2009, and was followed by a world tour that was documented by the Internet reality show Welcome to Wonderland. An English version of the single "Nobody" arrived that same year, along with another tour, this time of America as the opening act for the Jonas Brothers. The group members' school and other obligations also meant that 2009 was a year of lineup changes, and by the Wonder Girls' 2010 tour of America and Canada, the membership included Sun (Min Sun Ye), Yenny (Park Ye Eun), Sohee (Ahn So Hee), Yubin (Kim Yoo Bin), and Lim (Woo Hye Lim). This lineup released the Wonder World album in 2011, followed by the Wonder Party EP in 2012. ~ Chris True