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Following the Battle of Culloden in 1746, the British Army desperately needed accurate maps of the Scottish Highlands if it was to govern the area. Young military engineer William Roy was given the task of producing them. Will his maps see Nick safely through the treacherous terrain?

Can Nick use the first ever road map - a 329-year-old document - to lead him over the notorious Trans-Pennine Pass? With the help of experts he tries the journey on his mountain bike in midwinter, having ago at dimensuration (road surveying), and finding old roads might fade away, but never disappear.

The 1933 tube guide revolutionised the face of underground mapping and travel for ever. Having realised two years before that circuit diagrams were a perfect model for a new map of the network, electrical engineer Harry Beck created the blueprint that's wholly relevant today. Why did he exclude everything at street level? What dictated his choice of colour for each line? Minding the gap, Nicholas Crane checks out the facts.

Created in the time of Geoffrey Chaucer, the 14th-century Gough map of Britain was a landmark in map-making and was still in use 200 years after it was drawn. But what do the red lines signify along the coast, and why is there a massive green wilderness dominating the centre of Wales? While exploring these mysteries, Nicholas Crane attempts to use the map to find his way on foot from Snowdon to St David's.

Before the late 1700s sailors couldn't fix their position at sea and had to sail close to land, increasing the risk of shipwreck. So when Greenville Collins' charts of Britain's coastline were published in 1693, hundreds of lives and ships were saved. Explorer Nicholas Crane navigates Cornish waters in a square-rigger of the period to reveal the extent of Collins's achievement.

No one thought rocks were that important until they studied Smith's revolutionary, multi-coloured geological map of Britain. Years before Darwin, Smith overturned all the existing ideas about mineral prospecting, fossils and the origins of the Earth. Modern explorer Nicholas Crane's investigation examines how Smith arrived at his ideas.

In just five summers, Saxton produced the first national atlas, providing Elizabethans with thirty-four beautifully engraved, hand-coloured county maps. But maps are created for all sorts of reasons and as he motorbikes across Norfolk (Saxton's first map), Nick discovers that Saxton's survey was as much about identifying possible political troublespots as rivers and windmills. Nick comes up with fascinating evidence that Norfolk was the heartland of Catholic conspiracy-making in the late 1500s. He also tries to solve the puzzle of Saxton's amazing omission from his Norfolk map: the Norfolk Broads.

Being an OS surveyor in the 1930s was back-breaking work, as Nicholas Crane discovers. Braving the wilds of the Scottish Highlands, he conducts his own triangulation survey - will his efforts measure up to the exacting standards demanded by Britain's national mapping agency?