London breathes on my back. Around me, shirts billow, dresses flare and hats are clutched, as the stuffy, tasteless air roars past us in search of somewhere to dump its heat. Behind me, the mournful screee of an Underground Tube train – and around me, a subterranean London that is far from solid.

Imagine laying a cross-section across the city, dividing it like a cake. Looking at the results, you’d think: earthworms. The ground under London is Swiss-cheesed with cavities. There are the most famous – the London Underground and its many, many abandoned stations, and the extraordinarily extensive sewer system pioneered by Joseph Bazalgette, the “Sewer King“, an engineering marvel now threatened from above. But around them, burrowed into the sponge of subterranean London, are countless other mysterious voids. The church catacombs, most notably at Camden. The military bunkers and citadels and their extensive tunnel networks.  The pedestrianways winding between Heathrow’s terminals (above), hauntingly endless when you’re dragging your suitcase down them. And then there’s the Fleet, London’s lost river, gushing back and forth through the sewer tunnels as the tide waxes and wanes, a trickle of its former self but still powerful enough to drown the unwary.

And through all this, the dead air of London’s ancient breath…

In.

Out.

Photo: Mike Sowden 2011.

Further reading:

• The real & fictional tunnels of London, at FictionalCities.

• Oh, and be sure to track down a copy of Neil Gaiman’s Neverwhere, book and BBC TV adaptation.