Krakow is arguably the most beautiful city in Poland, and its old town - designated a UNESCO World Heritage Site way back in 1978 - is still pretty much original. The royal capital of Poland for many centuries, the architecture is a mixture of Renaissance, Baroque, and Gothic.
Visit the Gothic Wawel castle on Wawel Hill for a view out over the city, and to learn about the magic stone - part of a Hindu legend - that allegedly kept the city safe during World War II, and check out the nearby cathedral, burial place of Polish kings and other national heroes.
The main square, with its Cloth Hall and its outdoor cafes, is great for lazy people-watching, and you can take in works by artists such as da Vinci and Rembrandt at the Czartoryski Museum.
From Krakow, it is easy to visit the sobering Auschwitz-Birkenau Concentration and Extermination Camp, or head to the Wieliczka Salt Mine to see the chapels, concert halls and statues carved from rock salt.