In 1930s the passages of the Swedish and Ingeri bastions were reconstructed as air and gas raid defence shelters which were to accommodate up to 1000 citizens in case of emergencies. The passages were employed as shelters also during the Second World War. During the Soviet period the civil defence shelters were equipped with independent electricity and ventilation systems, water supplies and central heating, there were even telephone lines. In late 1980s the passages were temporarily used for storing the sculptures of the Estonian Art Foundation, however, in early 1990s the passages came to be inhabited by homeless people who remained there until the beginning of the new century.