Place From 1613
The so-called New River is actually an aqueduct built 1609 - 1613 from near Ware, Hertfordshire, to Islington to bring fresh water from country springs to the City. It required a 1602 charter from King James I. Now, 2007, the New River is still used as a source for London's drinking water and also provides a 25 mile footpath. See also the remains of the windmill. Diamond Geezer has a very comprehensive post. And here is the walking guide.