Known as "fatbergs", these blockages form when waste such as cooking fat and wet wipes are disposed of down drains and toilets. This particular fatberg contained delights including tennis balls and planks of wood.
A team of sewer experts spent most of last week battling the giant fatberg, fighting it with high powered water jets.
It was removed to prevent the sewer flooding, which would have involved nasty sewer waste filling the homes and businesses of Shepherds Bush. So thank you fatberg fighters.
The water firm says unblocking sewers costs London 12 million a year. So next time you consider flushing a wet wipe, or a tennis ball, think of the words of Dave Dennis, Thames Water sewer operations manager, "London - bin it, dont block it."
Getty Images Dean Mouhtaropoulos / Flo Perry