The Changing of the Guards is a customary performance that is re-enacted daily at Buckingham Palace as well as at the Horse Guards Parade, Whitehall.
The Changing of the Guards here started at 11am, and kicked off with a group of navy-cloaked horsemen moving out into the court yard. A few minutes later, they are joined by red-clocked horsemen. Lots of shouting later, they would finally move around the ringed area.
A great tourist attraction.