‘Of the great sewer that runs beneath, Londoners know, as a rule, nothing, though the Register-General could tell them that its existence has added some twenty years to their chance of life.’

So wrote The Times in their 1891 obituary of Joseph Bazalgette, the engineering genius behind London’s Victorian sewers. In it, they evoke the image of Gustav Doré’s 1872 print ‘The New Zealander’, which shows a cloaked figure gazing across the Thames at the ruins of St Paul’s. How prescient the Times were in calling to mind Doré’s apocalyptic vision, for, just 126 years later, London would be brought to its knees by a coagulated mound of fat, nappies, oil and condoms dubbed ‘The Fatberg.’

The Fatberg is 250 metres long and weighs 130 tonnes. That’s about four times longer than Cutty Sark, though only a seventh as heavy. That’s a less random counterpoint that it at first seems: Cutty Sark was built in 1869, at the same time that Bazalgette was setting to work on his sewers. Imagine if, in 2017, Cutty Sark was still at sea, selling and buying tea to and from our remaining free trade allies. Imagine she were not simply a novelty, but the height of competence and beauty. Imagine she were not subject to regular arson attacks and held together with sellotape.

It seems incomprehensible—but that is the effective status of our Victorian sewers. They are not a tourist attraction, roped off in a dry dock, but a living, essential part of modern London. When someone uses the top most toilet in The Shard, that flush will find its way through the Qatari-owned neo-futurist furnishings of its host, and eventually end up travelling the same route as every Londoner’s excretions since Disraeli was Prime Minister.

In 1861, when Bazalgette broke ground on his plumbing system, London’s census recorded a population of 2,803,034. It had been the world’s largest city from 1815, but had tripled in size since then. With it came a sanitation crisis born of overcrowding in slum tenements coupled with enormous demand on a limited clean water supply. Into that mix strode Bazalgette, tasked with building more than 80 miles of underground rivers, as well as over a 1000 miles of street sewers. Bazalgette applied himself to the task with the rigorous hard work of an engineer, but also the eye of an artist.

The Victorians had something of a mania for aestheticizing the mundane and macabre. The MP John Bowring called the new wave of cemeteries “a great theatre for public taste” and the sewer system was built with the same intention. Vaulted ceilings and a scale more appropriate to cathedrals—one almost expects to see Quasimodo come punting around the corner on that sea of sewage—speak to a time when effluence had an almost religious significance, especially given the cholera epidemic in 1853 that had killed almost 11,000 people. Above ground, things are even more dramatic: the pumping stations at Abbey Mills and Crossness are amongst the most beautiful of London buildings, the latter being described by Niklaus Pevsner as “a Victorian cathedral of ironwork.”

Last year, the new Thames Tideway Tunnel project finally got underway. Despite being built by a construction firm called Bazalgette Tunnel Ltd, the new “super sewer” is, like most modern infrastructure projects, enormous in its scale, but not its ambition. The chairman of the original steering group for the project has already called it “a waste of about £4b” and it has also been condemned by local residents for its ugly, noisy pumps. My father even had to move home when they started work outside his bedroom window.

The Fatberg is a chance to celebrate Bazalgette’s original vision and its near-flawless execution. He routinely defied other surveyors, making bigger and wider than they thought necessary. In 1861, the population of the entire United Kingdom was just 20 million, and to most Victorian planners the idea of a metropolis of almost 9 million inhabitants would have been incomprehensible.

And yet the sewer system they built in a sanitation crisis still works, almost perfectly. It’s a stunning argument against short-termism, NIMBYism and the mediocrity of modern bureaucratic ambition. If our current housing crisis was addressed with the same zeal, who knows what kind of city the New Zealander could be looking upon in another hundred and fifty years.

The Fatberg will be removed in a couple of weeks, and the sewer will start flowing again. But the Times was right: Londoners, as a rule, know nothing about the living history beneath their feet, whose storied tale is written on with every flush of your loo.