Changing Of The Horse Guards

There is a military unit called the Horse Guards, which are stationed on Whitehall, just down the street from where the Prime Minister lives. (As an aside, I learned on the tour that Tony Blair opted to live in 11 Downing Street, and not the customary 10 Downing Street, as 11 Downing Street is larger). The Horse Guards have a daily changing of the guard ceremony (which is distinct from the daily, and more famous, changing of the guard ceremony at Buckingham Palace).