Minster Pool

Minster Pool is a reservoir located between Bird Street and Dam Street in the heart of the city of Lichfield, Staffordshire in the United Kingdom. The pool lies directly south of Lichfield Cathedral and historically has been important to the defence of the Cathedral Close. The pool was originally formed in the 11th century when a boggy stream was dammed at its eastern end to drive a mill on Dam Street. The pool was used as a mill pond and fishery until 1856 when the mill was demolished; it has since been retained for public amenity.

Source: Wikipedia