First twisted skyscraper

The first twisted skyscaper is the HSB Turning Torso in Malmö, Sweden, based on a sculpture called the Turning Torso. It was begun in 2001, completed in 2005 and was designed by architect Santiago Calatrava (Spain). The core is a concrete pipe and walls, which gradually go from 2.5 metres in thickness at the bottom to 0.4 metres at the top of the building. A structural slab fits around the pipe and is shaped like slices of a pie. The forms were rotated 1.6 degrees for each floor in order to create the characteristic twist of the building, which looks like turning cubes. A steel support runs around the exterior. The glass and aluminium facade is double curved with approximately 2,313 panels and 2,368 windows. The panels are curved and the glass panels are flat. The windows lean inwards or outwards, depending on which side of the building they are on, between 0 and 7 degrees, while the lateral lean is about 6 degrees.