The Old Town of Krakow is sensational.
Start at the northern point with the Barbican and St Florian's Gate, wander down Ulica Florianska, arrive at the Old Market Square (with incredible buildings such as the Cloth Hall, St. Mary's Basilica and the Town Hall Tower), then continue south along Ulica Grodzka (with the Church of St Peter and St Paul, the Church of St Martin, the Church of St Andrew and the Church of St Giles and much much more) and finish off at Wawel Castle & Cathedral.