Danube Cycleway, Germany-Hungary
Arguably the most popular long-distance cycle route in the world, the Danube Cycleway ushers riders from south-west Germany to Budapest. The entire 850-mile route can be broken into smaller stints easily. Like the river, the trail meanders through wild gorges and pockets of civilisation.
Details Cicerone publish a guide to the cycleway (www.cicerone.co.uk)