Ben Nevis Cover Image. 1:25 000 scale (4 cm to 1 km – 2.5 inches to 1 mile) The essential map for outdoor activities. Planning to do the Three Peaks challenge? Find a pre-planned route for each peak plus essential safety information. OS Explorer Map is the Ordnance Survey’s most detailed folding map and is recommended for anyone enjoying outdoor activities including walking, horse riding and off-road cycling. Providing complete GB coverage, the OS Explorer map series details information essential in the great outdoors, including youth hostels, pubs and visitor information. Rights of way, fences, permissive paths and bridleways are clearly shown, ensuring you have the best information to get the most out of your time in the countryside. The Three Peaks Challenge Map featuring :-A safe and approved walking route for each peak, A quick guide to the history of each peak, Hazard warnings, Map legend exclusively for this map, Parking information, Map contains the mapping for ALL Three Peaks.