Zitadelle Spandau, located in Berlin-Spandau, is one of the most important and best preserved fortresses of the renaissance in Europe. It is a landmark of its district and arena of many knight fights and other events. In the summer, a lot of open air events take place in this historically stunning location. The popular Citadel Music Festival, for example, invites internationally well-known artists like Lenny Kravitz, Nena, Nine Inch Nails, and and Massive Attack.