London, England: Horse Guards Building

The Household Cavalry is a military unit that has taken part in every British action by its armed forces since 1660. Think about that for a while - 365 years. The Horse Guards is a building that serves as the barracks and stables for that Household Cavalry.  

Got it? 

The relationship of the various elements that use this building comes off as rather complicated. The building hosts the Household Cavalry Museum, and the Cavalry Guard itself has performed the King's Daily Guard for more than 350 years. Occasionally the unit supplies a guard for the King when he is out and about in London, and the members sometimes serve in military roles across the role when needed. 

By the way, there's a large open space behind the building. That serves as something a link to St. James's Park, one of the best open spaces in all of London. 

To simplify matters, concentrate on a couple of guards on horseback that watch over the front of the building. Every hour, they change the personnel and the horses around - which is a good way to attract a crowd. (There are time restrictions on how long a horse can sit there with a person on his back.) It's all done with spit-and-polish military precision. It's a good-sized tourist attraction.