Despite the increasing building density on the Rhine riverfront south of the city centre, the Cologne Oval Offices were designed to maintain the landscape qualities of this area. The two offset volumes also help to integrate an existing 12-storey block into the lower-height urban fabric. Each volume contains three cores, around which the functional areas are laid out in a curving strip. Internal finger-like soffit “sails”, which play an acoustic role, also serve to define working zones and to mask various technical systems. The architects drew up the concepts for the different kinds of offices, whereas the internal finishings were executed in accordance with tenants’ wishes. The extensively glazed facade allows good daylighting, while nearly 5,000 external folding shutters reduce solar heat gains. Printed externally in various shades, the shutters lend the outer skin an iridescent coloration. In summer, temperatures are cooled by a heat-exchange unit using filtered water from the Rhine at 14–16°C. In winter, the circuit is warmed by means of district heating.