By Brady Haran
Is this sewage outlet the "fountain of youth"?
The small waterway behind Nottingham's Queens Medical Centre looks unspectacular, but may help unlock the secret to increasing human lifespans.
Scientist Aziz Aboobaker and fellow researchers use the outlet as a source of planaria (flatworms).
They say the worms are helping us understand stem cells and leading to advances in human medicine.
The planaria are special because they have a high proportion of adult stem cells, with Dr Aboobaker nicknaming them "immortal worms".
He says: "The coolest thing is that we can take a worm in the lab, chop its head off, and within seven days the worm has grown a whole new brain.
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