Is Madonna a greater artist than Taylor Swift? As one musical titan continues her tour, another sets on the road. But pop fans are fiercely divided over which one is the true queen of pop.
It’s Madge v TayTay for greatest of all time
Face off: Both Madonna and Taylor Swift have become multimillionaires due to their musical success. Glossary
California - A large state on the west coast of the USA. It is the country's most populous state, with more than 37 million people. First settled by Native Americans as much as 13,000 years ago, the area was subsequently conquered by Spain, then was absorbed into Mexico, which was forced to hand it over to the USA in 1848.
Swifties - Fans of singer Taylor Swift.
O2 - An entertainment area built within the dome of a building that used to be called the Millennium Dome in Greenwich, south east London.
Grammys - The most prestigious award in the US music industry. The trophy is shaped like a gilded gramophone. Last year, Billie Eilish won most of the main awards.
VMAs - The MTV Video Music Awards
Hypocrisy - When someone pretends to have beliefs, feelings, or standards that they do not really have or follow.
Reggaeton - A style of popular electronic music that first emerged in Panama in the 1980s. It is popular across the Spanish-speaking Caribbean.