I went to London with my BFF in October 2009 and we met up with my niece who was living in Birmingham at the time. We had amazing weather for doing all the touristy things.
We literally stumbled upon this. We were walking along and T spotted the crowds gathering, so we quickly went in and found a good viewing spot and waited for the pomp to begin.
The 18th century Horse Guards building facing both onto Whitehall and onto the Parade is a much admired part of Royal London's architectural heritage. Designed by William Kent, c. 1748, and completed in 1759 by his disciple John Vardy, it is an impressive Palladian backdrop to this and other colourful Royal ceremonies and events which take place annually here, such as Trooping the Colour ceremony marking the Sovereign's official birthday in June, Beating the Retreat and the Remembrance Sunday Royal March Past of veterans in November.