It’s hard to believe that 15 years have passed since Backstreet Boys redefined the modern musical landscape, ushering in a chapter of pop culture that commandeered the world’s radio airwaves, broke music and concert sales records, and launched a new generation of teen idols for millions of youth. You were there: Remember the cool, silken harmonies, the passion-fueled mania that followed their every move? Perhaps you even had a BSB poster on your wall.

In all, the group has sold more than 75 million albums worldwide. Their first two U.S. releases both received the Diamond Award for sales of more than 10 million: “Backstreet Boys” in 1997 and quintessential “Millennium” in 1999, which reached No. 1 in 25 countries. They have scored a dozen top 40 hits, including top 5 smashes “Quit Playing Games (with My Heart),” “As Long As You Love Me,” Everybody (Backstreet’s Back)” and “All I Have To Give.”

A lot has changed since 1997, when we first got to know the five singers comprising Backstreet Boys: Nick Carter, Howie Dorough, Brian Littrell, AJ McLean and Kevin Richardson. Today, like their fans, they have grown up and started families, recorded solo projects, and appeared on the Broadway stage, all while dealing with the trials and tribulations that accompany fame at an early age, including substance abuse, management snafus and even major health issues. Also notably, in 2006, Richardson amicably decided to exit the group, with the full blessing of his teammates.