"Many people who live in Vienna are convinced they know the city like the back of their hand. But a lot of it is hidden, and many interesting buildings are not usually open to the public,” Open House organiser Iris Kaltenegger said. The event will take place on September 13th and 14th.

There will be guided tours of several buildings, with residents and architects who have interesting stories to tell.

Of the 70 buildings which will be open to the public, one third are residential, one third are commercial or office buildings, and the rest are educational or recreational facilities.

The 1930s Karl-Marx-Hof apartments (used as a filming location for The Night Porter), the Anker bread factory, a coffin factory and the Austrian Postal Savings Bank designed by Otto Wagner are some of the buildings that will be open.

The Postal Savings Bank has a special vault containing its archives – which include Emperor Franz Joseph’s first savings book and Wagner’s blueprints for the building.

The event is free and you don’t need to register.