From the photo archives: Madonna

'Who's That Girl?'

From the very beginning of her career, Madonna became known for frequently changing her look, as well as for provocative stage performances. For her 1987 "Who's That Girl" tour, Madge went through seven costume changes and used video projection screens to deliver messages critical of President Ronald Reagan and the Pope. It became the highest-grossing concert tour of all time—until Michael Jackson's "Bad" tour topped it the following year.