The Queen of Pop continues to reign! As Madonna launches her Celebration world tour these are her biggest albums...

After a postponement caused by a health scare in the summer, Madonna launched her long-awaited 'Celebration' world tour at The O2 in London last weekend. The show spans her five-decade career and sees the 65-year-old singer performing songs like 'Holiday', 'Vogue', 'Like A Prayer' and many more. There's no doubt Madonna - who released her debut single with Warner in 1982 - has earned her Queen of Pop title. These are Madonna's 10 highest-grossing albums from her legendary career...