Offa’s Dyke Path is a walking route which follows an ancient man-made feature. In some places the dyke is an earthen wall with a steep high bank, at others a deep ditch or a hedge. The path is 176 miles long and runs from Chepstow to Prestatyn. The route takes in beautiful parts of the Black Mountains, Hay on Wye, the Clwydian Hills, the Rivers Usk and Severn. Many walkers who travel the entire route pick up a pebble from the sea at the start of the walk and toss it into the River Wye at the end.