Two residential building complexes are located in 50 Marszałka Józefa Piłsudskiego Alley and 139 Świętojańska Street. They were designed in 1930 by the architect Bohdan Lachert Msc – one of the key modernist architects of the 20s and 30s of the 20th c. The construction was initiated by the Social Insurance Company, thanks to a decision by the City Council concerning additional funds for 1930-1934 and support from the State Construction Fund. In September 1931, the construction of the first two-building complex on the corner of Piłsudskiego Alley (initially Kasyna Street renamed in March 1931) and Gerenerała Bema Street. A month later, the second complex was built in the corner of Świętojańska Street, Kopernika Street and Biskupa Dominika Street.
The complex in Piłsudskiego Alley consists of two parallel, four-storey buildings on an L-shaped plan. The building has a basement and there is a mezzanine with a row of windows over the last floor. There are sixty large apartments in the facility, from 60 to 85m2. The building was divided into five segments with door openings. On the Piłsudskiego Alley side, there are balconies with curved, openwork, metal corners and full balustrades in the middle. The brown, metal handrails, the balcony slabs and the base faced with clinker tiles contrast with the light, grey plaster elevation. Little, rounded roofs which protected the balcony and its users from rain were later added to the façade over the fourth floor. On 8th October 1931 at 7.00 PM, there was a gas explosion. It did not damage the entire building structure. One corner was destroyed, together with twenty apartments. This disaster killed 13 people. The destroyed part of the building was reconstructed and in 1994 an extension was added and the “Anker” pizzeria was established there (it is still open today).
The second complex in Świętojańska Street consists of three buildings. They are Art Nouveau gallery-access blocks with multiple staircases which accommodate 170 apartments from 28 to 45m2. The plan included yards between the buildings, two shops, garages and laundry (the last element designed by Stanisław Miecznikowski was not completed). The buildings’ bodies’ only distinctive features are the balconies with rounded corners and the galleries with openwork balustrades facing the yard.
Both complexes are sparing in architectural details with the light plaster shades and rounded corners. These were blocks for the clerks of Office Worker Insurance Company in Poznań.