This gigantic fatberg, made up of oil, grease, wet wipes, and nappies, was found blocking London's sewer systems.
The huge blob weighed 130 tonnes - roughly the same weight as 11 double decker buses. It also measured 250 metres in length, which was about the same as two football pitches.
Thames Water engineers are working to clear the fatberg, which they think will take around three weeks.
Thames Water’s head of waste networks, Matt Rimmer, said: "This fatberg is up there with the biggest we’ve ever seen. It’s a total monster and taking a lot of manpower and machinery to remove as it’s set hard.
"It’s basically like trying to break up concrete. It’s frustrating as these situations are totally avoidable and caused by fat, oil and grease being washed down sinks and wipes flushed down the loo."
Produced by Claudia Romeo