AT one point during the recent royal wedding, the coach carrying the just-married Duke and Duchess of Gloucester passed under an archway en route to Buckingham Palace, giving the world a view of a large, gravelled square: Horse Guards Parade.
Keep that glimpse in mind as you build up to the Olympic Games in London in July to August next year, because you'll be seeing a lot more of it - though in slightly unexpected circumstances.
The parade, which dates back to 1745, forms a link between Whitehall and the long, straight stretch down The Mall to Buckingham Palace, and it has long been a focal point for British pageantry.
On consecutive evenings each year - this year it took place on June 8 and 9 - it is the scene of the military ceremony of Beating the Retreat, featuring the massed bands of the Household Division performing spectacular marches, bagpipe tunes and hymns in one of the most important events on London's ceremonial calendar.
It's also the site for Trooping the Colour, which marks the Queen's birthday each year. In tourist terms, it is a landmark site.
The parade ground faces Horse Guards Rd and St James' Park, and the rear garden wall of 10 Downing St abutts its south side. Statues of the field marshals Kitchener, Roberts and Wolseley look down from the edges.
With that backdrop of pomp and pageantry, take your mind forward to July 28 to August 9 next year, when that famous patch of ground will be taken over by bikinied Amazonian women and bronzed giants wearing baseball caps, as Horse Guards Parade becomes the venue for the Olympic beach volleyball contest.
Of all the Olympic venues in London, that is a strong candidate for the most incongruous setting.
I wonder what Lord Kitchener - of the fierce stare and bristling moustache on the famous 1914 war-recruitment poster - would make of semi-naked 1.9m-plus Brazilian and American women lunging about in the sandpit.
Temporary seating will be erected around the sandpit to accommodate up to 15,000 spectators. If you can get there you should, because it will be a once-in-a-lifetime opportunity.
Not surprisingly, Horse Guards Parade is not going to become a legacy beach volleyball venue. The stands and sandpits will be removed as soon as the Games end.
But it should be a great venue because, apart from all that history, there are five underground stations within easy walking distance. The odds are it will be one of the more over-subscribed events on the Games programme.
But it is not the only sport being based at an unusual venue.
There's also archery, which will take place at Lord's, cricket's most famous ground and once the headquarters of the International Cricket Council. Then there's Hampton Court Palace, King Henry VIII's favourite home, situated beside the River Thames, about 19km from Waterloo Station. It will be the start and finish line for the cycling time trials - 44km for the men, 29km for the women.
While there, you can take in the splendour of the palace and its world-renowned maze. Take the ghost tour and remind yourself which of Henry's six wives got the chop, and who survived.
Hyde Park has its place on the Games programme as the venue for the triathlons. That will include a dip in the Serpentine lake for the swimming leg which, needless to say, will need a clean-up.
The approach road to Buckingham Palace, with its gilded gates, will form a spectacular part of the marathon course. But for me the beach volleyball at Horse Guards Parade has got to be the most remarkable offering on the programme.
Update your news preferences and get the latest news delivered to your inbox.