We descended 60 metres below ground to see the vast new sewer system that will to transport Londoners' bowel movements for decades to come.
As a new Channel 4 show explores the mysteries of the fatberg, we went along to look at (and smell one) for ourselves.
In efforts to put brands into everything, an edgy and illegal exploration becomes just another extreme sport.
In the words of its inventor, the product is a potent combination of "butt crack, kind of a sewer smell, with a hint of dead animal."
Spoiler: lots of fucking disgusting stuff.
Urban explorer Substormflow takes you "draining" inside the city's brick and concrete tunnels.
Bucharest's foundations are home to dozens of deformed children.