With the rehabilitation of this former works site, a new development has been created on one of the largest derelict industrial areas in Berlin. “Oberbaum City”, as it is known, comprises offices, housing and commercial properties. The existing listed buildings erected between 1903 and 1908 were initially used by the Osram company and later by the East German Narva light-bulb organization, which was dissolved after the reunification of the country. In the comprehensive programme of refurbishment and conversion undertaken by the Hamburg architects Schweger + Partner, some of the buildings had to be gutted to remove the mercury – used in the production of light bulbs – that had accumulated there. The ensemble now consists of three buildings: a new structure that follows the plan forms of the existing development; a refurbished building, the facades of which underwent extensive restoration; and a tower, which has been raised in height by five storeys. The new Narva Tower, with an overall height of 63 m, is 24 m taller than the former brick building. All that remained of the old tower were the outer walls. The new five-floor glazed volume on top is separated from the existing structure by a storey-height void and is crowned by a services floor. The head of the tower was constructed with a double-skin facade that allows natural air conditioning of the office spaces.