Task: Question Generation
Input (English): In mid-2004 Madonna embarked on the Re-Invention World Tour in the U.S., Canada, and Europe. It became the highest-grossing tour of 2004, earning around $120 million and became the subject of her documentary I'm Going to Tell You a Secret. In November 2004, she was inducted into the UK Music Hall of Fame as one of its five founding members, along with The Beatles, Elvis Presley, Bob Marley, and U2. In January 2005, Madonna performed a cover version of the John Lennon song "Imagine" at Tsunami Aid. She also performed at the Live 8 benefit concert in London in July 2005.
Output (English): What was Madonna's documentary called?