Trooping the Colour in the U.K. is a celebration of the reigning monarch's birthday. It's held every year in June, regardless of when their actual birthday is, and it involves a lot of fanfare with a parade and a dramatic RAF flyover.

The annual display of British military might serves as a seasonally tweaked birthday celebration for the sitting monarch.

Queen Camilla wore a sour expression during the Trooping the Colour Parade, which got many online users speculating about what had happened to her face.