Herkules-Hochhaus

The façade is clad in enamelled metal panels in blue, orange, red and lilac, with silver-framed windows divided into three parts and arranged in a free, non-repeating rhythm — a hallmark of Neufert's 'systemic architecture'. Rather than a rigid grid ('Rasteritis', as he called it), the varied exterior conceals a flexible interior layout. Apartments range from 24 to 33 square metres; two-room flats measure 43 square metres, and each floor has two three-room units facing the direction of Cologne Cathedral.

The building has a concierge and four lifts that stop alternately on even and odd floors. The ride from ground level to the 31st floor takes about a minute. Residents — largely students and international tenants, with a relatively high turnover — share access to a rooftop swimming pool, sauna and party room.

Cologne residents were never fond of the tower: an architecture journal declared early on that 'the housing factory puts off its neighbours'. In 2005 the Kölner Verkehrsverein awarded it the 'Saure Zitrone' (Sour Lemon), a booby prize for unattractive architecture. On 11 January 1979 a candle started a fire on the first floor; one young man died in the lift and another was seriously injured jumping from eight metres to escape the blaze.