Queen Elizabeth II: Celebrating Her Majesty's 90th Birthday Learn about the longest-reigning monarch in British history in a minute.

 -- The queen of England, the longest-reigning monarch in British history, is celebrating her 90th birthday on April 21, 2016.

Born Princess Elizabeth Alexandra Mary in 1926, her majesty was not in line to become queen until her uncle abdicated the throne. Some fun facts about the queen: she was nicknamed "Lilibet" by her family as a child, and she volunteered as a mechanic during World War II.

Watch the video above to learn more about Queen Elizabeth II in a minute.