Żoliborz is a green-filled district with a partly residential character, renowned for the 19th-century Warsaw Citadel, which was once home to extensive Russian barracks. Currently, there are several museums located here, including the Katyn Museum, which commemorates Polish soldiers murdered in 1940. Within the charming Kępa Potocka Park lies a lake surrounded by willow trees. Along the Vistula River, there are paths for cyclists and runners, and in the summer, urban beaches and laid-back bars come to life.