Looking up one day whilst visiting Barcelona, Lisa Rienermann realised that the letter Q was formed by the shapes of the roof tops and the sky. She went on to search the city for other examples that would give her the entire alphabet. It took her several weeks but she eventually achieved her goal.
She has also created a font from sections of city maps.
Designer Tim Fishlock has used the iconic London Underground map to create this A to Z.
Source - 'Alphabets, A Miscellnany of Letters' black dog publishing