Britain's Prince William and Kate, Duchess of Cambridge, with Prince Harry, left, and his fiancee Meghan Markle, third left, attend the first annual Royal Foundation Forum in London, Wednesday Feb. 28, 2018. This is the first official sighting for the two royal couples of the British monarchy, although the four were first seen together in public during Christmas.

Look at events and milestones celebrated by the royal family.

Photo Credit: Chris Jackson/AP