King Jan Olbracht himself laid the cornerstone and supported the project with a significant sum of money. The Barbican in Kraków was erected in the 15th century and for years it was virtually indestructible. It survived even in the 19th century, when an initiative to restore order in the city was launched and the fortifications were dismantled or demolished. Today, it is one of the few surviving works of defensive architecture of its kind in Europe. It is connected to the rest of the city by two gates, leading to Kleparz and the city walls. Today, the Barbican is a branch of the Museum of Krakow. It used to be surrounded by a semi-circular moat, 26 metres wide and up to six metres deep, which was filled in in the process of urban sprawl and growth. The underground part of the building was a vaulted walkway that led to special gates which allowed soldiers to leave the building via the moat. Today, the building is considered to be the most beautiful of all Gothic buildings of its kind which have survived to this day in an unchanged state. There are not many of them – you can see other remaining ones in Carcassonne and in Görlitz.