Anyone who's visited London in recent years will have seen - and narrowly avoided being run over by - a "Boris bike".
Once blue, they are now slowly turning red (thanks to a switch in sponsorship from Barclays to Santander, rather than any prolonged exposure to the sun).
Since 2010, the Transport for London hireable cycles have helped plucky visitors and commuters navigate the capital's frantic streets from as little as £2 a day. Provided you can find a docking station with a functional bike and in possession of the patience/mental capacity to decipher the payment system.
TFL has looked to ease this final niggle with a new free app that allows you to reserve a bike from your phone.
All users need to do is register a bank card, find which of the 750 docking stations is nearest and hit 'Hire Now' to book one of the 11,500 bikes. The app will then give a bike release code available for a ten-minute window (you won't be charged if you don't use it).