The Brothers Grimm lived in Kassel, their mother's hometown, as teenagers, and also worked there as librarians at the court of the king of Westphalia, Jerome Bonaparte (Napoléon's youngest brother), and for the elector of Kassel. In researching their stories and legends, their best source was not books but storyteller Dorothea Viehmann, who was born in the Knallhütte tavern, which is still in business in nearby Baunatal.
Much of Kassel was destroyed in World War II, and the city was rebuilt with little regard for its architectural past. The city's museums and the beautiful Schloss Wilhelmshöhe and Schlosspark, however, are well worth a day or two of exploration.