Underneath the streets of the English city of Exeter their lies a network of medieval tunnels. For hundreds of years they were used to bring fresh drinking-water to the city.
Following the lead of the city of London, Exeter had lead pipes bringing water from a natural spring into the public fountains in the centre of the town. However, by the fourteenth-century the pipes were springing leaks and need to be dug up so much that the citizens decided to build a system of underground tunnels where the pipes could be placed.
http://www.medievalists.net/2014/06/medieval-plumbers-exeter/
https://www.youtube.com/watch?v=jT4SrBjjrog
