The Greenwich Meridian Trail is a new long-distance walk from Peacehaven in East Sussex to Sand le Mere in East Yorkshire, following the line of the Prime Meridian. The total length of the trail is 273 miles (439 km). It is divided into four parts, this guidebook covers the fourth part which begins in the Lincolnshire Fens before crossing over the peaceful and unspoilt Lincolnshire Wolds to Louth and then to the Humber Estuary. A bus (or boat) ride takes walkers to the last section through Holderness to finish on the coast at Sand le Mere with its big beach, and where the sea and the sky vie to produce the most shades of grey and blue. The guide uses ordnance survey maps for easy route finding and is full of information about the places you will visit and stay at along the way. Good access by public transport makes it easy to do the walk in sections.