German railways (DB) doesn’t just run sexy-looking trains; now it also rents out space age bikes for €0.06 per minute (max charge €15 per 24hrs), or €1 for 30 minutes, with no deposit. The silver-red bicycles, known as CallBikes can be found parked throughout the centres of Berlin, Frankfurt and Munich. They're pretty heavy, but ride very smoothly with their shock absorbers, eight gears, semi-basket on the back and working lights. To use one (or two), all you need is a mobile (to use the app) or a public telephone and a credit card. Call the DB hotline (€0.06/min) to register and to get more information.