The Offa's Dyke Path

The Offa's Dyke Path is a national trail which traverses the length of Wales, roughly along the English-Welsh border. It was officially opened in 1971, and it's the forth of 15 national trails that have been formed in England and Wales.

  
Map courtesy of Contours Walking Holidays www.contours.co.uk

In parts it follows the length of 1200-year old earthwork which the name of the trail comes from. Offa was the king of Mercia from 757AD-796AD, in an area today known as the English Midlands. It is believed that the dyke was built to protect Mercia's border with Powys, and the workforce required has been estimated at 5000 men. 
The trail itself is diverse in nature. It travels through the Clwydian Hills, along canals and besides the Severn and Wye rivers, over the Shropshire Hills and the Black Mountains.
It is 177 miles (285km) of amazing walking, with picturesque and varied terrain.