Indigo Nights

In 2007, Prince set out to make history: He would be the first artist to perform 21 consecutive sold-out shows at London's O2 Arena, playing in front of roughly 350,000 people over the course of just two months. And as if that wasn't enough, Prince also announced that he would perform a series of late-night aftershows at a smaller club set up within the venue called the indigO2, keeping the party going into the early morning hours.

Prince's record-breaking feat was documented by the famed photographer Randee St. Nicholas for a collaborative book, 21 Nights, her photographs were accompanied by a live disc of aftershow recordings at the indigO2 called Indigo Nights. In addition to several live versions of previously released Prince songs like "Girls and Boys," "Delirious," and the title track of his 2006 album 3121, Indigo Nights also included covers of acts ranging from Led Zeppelin to Aretha Franklin and two unreleased songs, "Beggin' Woman Blues" and "Indigo Nights."

Although sales of the CD could not be tracked because it was never sold separately, the 21 Nights book reached number 9 on The New York Times best-seller list.