In fact it represents more than 2,000 square kilometres of river systems (that’s about 35 miles by 25 miles) in the West Midlands centred on Oldbury.
The white areas are the high ground (including the diagonal limestone ridge from Sedgley to Northfield). In the bottom left are the lower, darker zones of the Stour and Severn valleys while, leaving the image in the middle-right, more dark spidery traces represent the tributaries of the Tame flowing east through Birmingham.
In the Black Country itself (the centre of the image) the rivers are small and difficult to navigate, leading to the popularity of the canals from the 18th century, and their legacy in the landscape today.
> Read more about why the altitude of the Black Country is important – Where the old bull is really on the level