All The Light We Cannot See by Anthony Doerr

Marie Laure lives with her father in Paris and is blind by the age of six.  Her father builds her a model of their neighborhood so she can memorize it and navigate the real streets.  When the Germans occupy Paris, they flee to Saint-Malo on the coast.  In Germany, Werner grows up enchanted by a crude radio he finds.  He becomes a master at building and fixing radios, which wins him a place with the Hitler Youth.  Werner travels throughout Europe, and finally to Saint-Malo, where he meets Marie Laure.