prime tower zurich is situated in the heart of the city on the site of the former maag cogwheel factory, where zurich has been undergoing a transformation process for several years. the octagon-shaped prime tower is the project unanimously chosen as the winner of an international competition involving top-ranking architects. the decision that came out in favour of the zurich architect team was influenced among other things by the crystalline exterior that stands apart from its neighbours, the fine movements and projections, the many uses of the large ground plan and the static design with the pre-stressed ceiling.