While the origin of currywurst is foggy at best, legend has it that in 1949 Berlin house frau Herta Heuwer traded beer to British soldiers in exchange for their curry powder.  Not familiar with the spice blend, she added it to her tomato sauce recipe.   This combination of familiar flavors with an exotic twist became an overnight sensation as Herta served it with veal and pork sausage at her street stand near Berlin's red-light district.  Imitators popped up all over the city and, wall or not, soon all over Germany.  Today 800 million currywursts are eaten every year in Germany, with 70 million in Berlin alone.  It has become such a part of the German culture that it is now traditional for Berlin mayoral candidates to take promo pictures in front of their favorite Currywurst stands.