Step into Leadenhall Market and look up — that ornate cream, green and maroon ironwork, the painted glass roof, the cobbles under your feet. It's gorgeous, it's Victorian, and if it looks a little magical, that's not an accident. This is where they filmed the entrance to Diagon Alley, the wizarding street, in the first Harry Potter film. The Leaky Cauldron doorway is here somewhere. Tourists find it constantly. Owls, sadly, are not provided.
There's been a market on this exact spot for about seven hundred years, but that barely scratches the surface, because underneath these cobbles is Rome. You are standing on the dead centre of Roman London, right on top of the old forum and its basilica — the great public hall — which was the biggest Roman building anywhere north of the Alps. The largest structure for hundreds of miles in any direction was right here, under a market that now mostly sells cufflinks and pints to bankers. When the Victorians dug the foundations for the ironwork above
you, they had to sink the columns unusually deep, because they kept hitting eighteen-hundred-year-old Roman walls and having to go around them.
And if you'd like to actually touch that buried Rome, you can. Down in the basement of a shop just around the corner sits a great lump of the old basilica's wall — a genuine chunk of the largest building in Roman Britain, parked in a cellar beneath a mode
