In addition to the old town, the city's district of Kazimierz is particularly notable for its many renaissance buildings and picturesque streets, as well as the historic Jewish quarter located in the north-eastern part of Kazimierz. Kazimierz was founded in the 14th century to the south-east of the city centre and soon became a wealthy, well-populated area where construction of imposing properties became commonplace. Perhaps the most important feature of medieval Kazimierz was the only major, permanent bridge ("Pons Regalis") across the northern arm of the Vistula. This natural barrier used to separate Kazimierz from the Old Town for several centuries, while the bridge connected Kraków to the Wieliczka Salt Mine and the lucrative Hungarian trade route. The last structure at this location (at the end of modern Stradom Street) was dismantled in 1880 when the northern arm of the river was filled in with earth and rock, and subsequently built over.