The M48 crosses the River Severn alongside the M4 on the original Severn Bridge, carrying local and commuter traffic and forming a diversion route in the event that the Second Severn Crossing is closed.
Today two motorways cross the Severn near Chepstow. But as recently as 1965, the only crossing was a ferry that carried six cars at a time, from Aust to Beachley.
One man's account of the building of the M4 through Wales, seen as he grew up in Swansea and witnessed it stage by stage - a tour of the motorway from its construction to the present day.