The Austria artist and architect Friedensreich Hundertwasser is said to have once called straight lines “the devil’s tools.”

Hundertwasser designed many buildings throughout Austria and Germany, but the Waldspirale is a loud testament to Hundertwasser’s hatred of straight lines and his allegiance to nature. Waldspirale translates to “wooded spiral,” and that is exactly what it is.

The large spiraled building is topped with an incredible forest - beech, maple and lime trees grow on the undulating, twisting roof. Completed in 2000 – the same year Hundertwasser died – the Waldspirale has 105 apartments and more than 1000 windows. Not one of these windows are shaped the same in this “out of line” building, and many have “tree tenants” growing right through them.

At the highest point the building has 12 floors. You can climb to the wooded spiral roof, which includes a cafe and a bar. Hundertwasser’s aversion to the “devil’s tools” is carried to the interior as well; the corners between the walls and ceiling are rounded off in every apartment. The Waldspirale is a testament to Hundertwasser’s organic aspirations and deep love of nature. As he once said, “If man walks in nature’s midst, then he is nature’s guest and must learn to behave as a well-brought-up guest.”

The Waldspirale was the last of Hundertwasser’s creations. He died in 2000, aboard the RMS Queen Mary 2 en route to Germany from Australia to view the work. Many more Hundertwasser creations can be seen in Vienna.

Update July 2016: The restaurant has closed and it seemed the building was not open to the public.