Dams built in the Elan Valley to the design of James Mansergh (1834-1905) created a series of reservoirs from which water was conveyed from central Wales to the city of Birmingham by a 118 km long pipeline. Materials were carried to the sites by a temporary railway, and the construction workers lived in villages of wooden huts. Work began in 1893 and the system was formally opened in 1904. Motorised and walking trails, focussed on an information centre 5 km W of Rhayader, enable visitors to gain an understanding of this remarkable feat of civil engineering. The pipeline to Birmingham is conveyed across a valley near Ludlow on a concrete viaduct, and over the River Severn on a bridge near Bewdley.