Known particularly for being a childhood play area for J.R.R. Tolkien and an inspiration for the look of the Shire, an important setting in his work, the Sarehole Mill is one of two remaining water mills in the Birmingham municipality. If you aren't a Tolkien fan (some folks don't see what the hoopla is all about), it is still a tranquil pond environment and a restored, culturally significant piece of Birmingham. There is a museum on site that you may enter for a 3 GBP ($4.50 USD) admission.
Note:Located on Cole Bank Road, Hall Green, Sarehole Mill is also within a few minutes time to a handful of parks and nature areas, including Moseley Bog and Swanshurst.