London Bridge, London

For pretty much as long as London has been… well, London, there’s been a bridge standing right here. The first one went up over 2,000 years ago, and since then it’s been a bit of a revolving door for bridges-Romans built one, William the Conqueror gave it a go, and King John had his moment too.

Back in 1014, when the Danes were running the show in London, King Ethelred the Unready-a man as prepared for battle as his name suggests-decided to team up with King Olaf of Norway and a band of Vikings. Yes, Saxons and Vikings were together at last. They sailed up the Thames, tied ropes to the wooden supports of the bridge, let the tide carry them downstream, and yoink!-down came the bridge. And just like that, the world got its catchiest medieval jingle: “London Bridge is Falling Down.”

By Tudor times, the bridge was basically a medieval high street, with 600 buildings, some six stories tall, crammed shoulder to shoulder. It was so packed, it became its own city ward. And as if bumper-to-bumper Tudor traffic wasn’t enough, the bridge also had a rather grim flair for home decor-namely, the severed heads of traitors displayed proudly on spikes. Yikes...

But the bridge couldn’t handle the modern hustle. By the 1960s, it was literally sinking at one end, buckling under the weight of traffic and time. So what did Britain do? Sell it, of course! For £1 million, or about $2.4 million back then, an American oil tycoon bought it, shipped it piece-by-piece across the Atlantic, and reassembled it over a lake in Arizona, where it stands to this day, probably wondering what happened.

The current London Bridge, built in 1973, is a minimalist affair: clean lines, pre-stressed concrete, some polished granite, and about as much flair as a spreadsheet. But hey-it gets the job done.

And once a year, for one glorious Sunday in autumn, the bridge trades buses and bikes for a flock of sheep. It's the Sheep Drive, an ancient right of the Freemen of the City, who lead their woolly companions across the bridge in a ceremony that's part tradition, part traffic-stopping spectacle.

Because why not?