In the 1990s, Vienna converted four former gas storage tanks into apartments, shops and offices.

The tanks, known as gasometers, were originally used to store town gas -- a fuel similar to natural gas that's made from coal. This was what many cities used to run things like street lamps in the late 19th and early 20th century. Vienna's gasometers remained in use until 1986, and were featured in the 1987 James Bond film "the Living Daylights."

Now the giant brick cylinders are known as Gasometer City, and are home to several hundred people.