Sewer workers say they think they've discovered the biggest ever lump of food fat under the streets of Kingston in Surrey.
The "fatberg", as its been called, weighs 15 tonnes and is as big as a double-decker bus.
It was found after residents complained that they couldn't flush their toilets.
Martin Stew drew the short straw, and went to have a look.
More top news
Murder investigation launched in Belsize Park after a woman dies in hospital from injuries.
Police launch a manhunt for an escaped violent sex offender after a boy was attacked and woman had her hair 'sprayed red' in west London.
A man has been rushed to hospital after a stabbing in broad daylight in West Kensington.