In 2017, crews working for Thames Water—a utility company that tends to the warren of sewer pipes snaking beneath London’s streets—came across something gnarly. Under the city’s Whitechapel neighborhood, a 130-ton, yellow-white mass of oils, grease, and trash, including gloopy wet wipes, was plugging up the pipes.

The stinky beast, which stretched more than 820 feet, was among the largest fatbergs ever discovered under the city, and certainly the most famous: The putrid mass spawned story after story about wanton wastefulness and the environmental toll of single-use products.

It took sewer crews more than three months to break up the fatberg and haul it to the surface. Bits of this fatberg or its rank brethren went off to labs for analysis, were dissected in front of television cameras, and were dried out and exhibited at the Museum of London.

Meanwhile, Thames Water and other utility companies around the world have doubled down on education campaigns to discourage residents from flushing anything beyond pee, poop, puke, and toilet paper. And in Whitechapel, Thames Water installed a manhole cover to commemorate the war being waged against the stuff sticking to the old pipes, and celebrate the unsung teams who slog through the stuff that shouldn’t be down there in the first place. Go pay it a visit, and pledge to never pour excess cooking oil down the drain again.