York Watergate

This ornate stone arch sitting in the middle of a garden looks completely out of place. That's because it is. When this gate was built around sixteen twenty-six, it was a boat dock. The Duke of Buckingham's grand riverside mansion stood behind you, and this gate opened directly onto the Thames. Servants would walk through it, step into a boat, and be on the water. It was the seventeenth-century equivalent of a private jetty.

Today, the river is a hundred and fifty metres away. The gate hasn't moved. The river has — or rather, London stole the riverbank.

In the eighteen sixties, the great Victorian engineer Joseph Bazalgette designed the Victoria Embankment. London's sewage was pouring directly into the Thames, cholera was killing thousands, and the stench was so bad that Parliament couldn't sit during summer — they called it the Great Stink of eighteen fifty-eight. Bazalgette's solution was a massive underground sewer system, and to build it, he reclaimed a huge strip of riverbank. The earth came partly from the excavation of the District Line underground railway, with topsoil brought in from Barking Creek.

Everything between this gate and the current river's edge was once water. The gate tells you exactly how wide the Thames was four hundred years ago. It's a measurement frozen in stone — a permanent marker of where London's shoreline used to be.

Most people walk through the Embankment Gardens without giving it a second glance. It looks like a decorative garden folly. But it's actually one of the most revealing objects in London — a four-hundred-year-old boat dock stranded a hundred and fifty metres from the water, proving that the city you're walking on is largely manufactured ground.