Members of Girls' Generation celebrate the group's 13th anniversary on Wednesday through Instagram, posting photographs they took on Aug. 1 for member Tiffany's birthday party in a dress code of black. "Thank you [fan club] Sowon for being with us for such a long time, and each of the members — congratulations to all of us […] There's no end to Girls' Generation, so let's toast to the happy days that we're going to spend together," wrote leader Taeyeon on her Instagram account. Girls' Generation debuted on Aug. 5, 2007, with "Into The New World." [SCREEN CAPTURE]