The only major city to escape the destruction of World War II, Krakow has one of the best-preserved medieval city centres in Europe. The Old Town is a significant UNESCO World Heritage Site and retains a wealth of architectural gems from different periods, with magnificent churches and aristocratic palaces lining the old streets, reminiscent of its glorious days when it was the abode of kings and royalty. At the heart of the city lies one of the grandest squares in Europe, the Old Market Square. The charming Old Town is a compact area encircled by leafy parkland that forms a green belt around the historic centre. The main entrance to the old city was through the Florian Gate, set within the original city walls, now the haunt of artists and their work. With a thriving cultural life, it has been home to many of the nation's greatest writers, artists and intellectuals, and is one of the main cultural centres in the country, a spirited city with personality and charisma. Overlooking the city is Wawel Hill, topped by the striking Royal Castle and Cathedral, the seat of Polish kings for seven centuries and the symbols of Polish national history. Also important is the city's Jewish roots, and the history of one of the great Jewish centres in Europe can clearly be seen in the old ghetto area of Kazimierz, and starkly remembered in the memorial death camps of Auschwitz and Birkenau, west of Krakow. Situated on the banks of the Vistula River, Krakow is also a modern city, the third largest in Poland, and an important university centre boasting the oldest university in Europe. The large student population creates a lively atmosphere and a vibrant nightlife. Countless cafes and outdoor restaurants surround the cobbled main square. The unique atmosphere of this medieval city has made it one of Poland's most popular tourist destinations.