Queen Elizabeth II is celebrating her 93rd birthday, which this year coincides with Easter Sunday.

The queen is marking Easter by attending a service with other senior royals at St. George's Chapel on the grounds of Windsor Castle, west of London.

Her birthday is marked this year by an unusual sunny spell that has sent flowers blooming on the extensive castle grounds.

Sunday is the first of two birthday celebrations each year for the queen. She marks her official birthday in June with the Trooping the Color parade.

The two-birthday tradition dates back more than 250 years, when it was instituted by King George II.

Elizabeth is the longest-reigning monarch in British history. She still maintains an active schedule, although she does not travel as often as she used to.