The site for the Mercantile Health Insurance Association in the Gross-Buchholz district of Hanover is characterized by large office buildings, company headquarters and the Medical University. For this reason a building type war chosen that can assert itself in its surrounding by its autonomous strength and repose. A lucid five- to six-storey perimeter development with a ten-storey tower providing approx. 750 workplaces is built around a peaceful inner courtyard. The inner courtyard forms the centre of the building complex: it is a spacious garden designed with greenery and water, and it can be enjoyed directly from the offices, and also from the entrance-hall, the conference foyer and the restaurant.