When your President met our Queen at Buckingham Palace last year, he rolled up in The Beast - a huge reinforced Cadillac built to resist bullets, missiles and chemical attack. There were also 200 Secret Service agents in tow, although what they got up to in the evenings in anyone's guess.
Buckingham Palace can be a risky venue for visiting dignitaries. Her Majesty is always perfectly charming, but Monty, Holly and Willow are a law unto themselves. These three little Corgi dogs may not look threatening, but they tend to chase people - and then bite. Five years ago the Queen was spotted with a bandaged wrist after intervening to break up a canine squabble. The wound to the Royal hand required three stitches.
Corgis were originally bred to help round up cattle. They usually go for your ankles. So when you see pictures of famous people with heads bowed in front of the Queen, they're probably on the lookout for her dogs. But, you're thinking, why doesn't she simply lock them up when she's entertaining? You don't know our Queen. She's had corgis for years. Her father King George the Sixth gave her a puppy for her eighteenth birthday. She's bred them. She's besotted by them.
They have their own official menu - poached chicken, liver, rabbits, pheasant - and home baked scones which Her Majesty crumbles and personally adds to their dishes every day. They have their own room in Buckingham Palace. And each Christmas Eve, the Queen fills three stockings with presents for her pets. These dogs accompany her everywhere.
At one notorious state banquet a Corgi - dare I say this? - indiscreetly pee'd on the rug. Her Majesty didn't bat an eyelid. She summoned the Master of the Royal Household, Rear Admiral Sir Somebody-or-Other, who commandeered a blotting pad from the Queen's writing desk and then went down on his hands and knees to deal with the damp patch. Everyone else pretended not to notice.
The Corgi breed has been in decline for a while. Only 300 puppies were registered every year. But they're now making a significant comeback thanks to Her Majesty's Diamond Jubilee and her three - sometimes ill-tempered - four-legged friends.
This is Ed Boyle for CBS News in London.