The tunnel saw renewed use only in the 1990s, hosting one of the first raves in Croatia, and functioning as a shelter during the Croatian War of Independence.

The plan was to construct the tunnel in 90 working days, but the cost rose to 490 million kuna (partly due to high wartime inflation) and the date of opening was delayed into 1944.

In February 1944, the Construction Committee of Zagreb, which was responsible for urban planning, issued a statement saying that the "creation of a shelter as a transport link is completely inappropriate," and that "too much attention has been devoted to it."

In May, the mayor of Zagreb, Ivan Werner, rejected the plans for a large central underground hall; instead, only the east-west corridor was built.

[4][9] A document dating to 31 October 1949 proposed the construction of another corridor connecting the existing one to the area of Gupčeva Zvijezda, about 2 kilometres (1.2 mi) to the north.

Emil Matešić, the director of the Cultural Informative Centre of Zagreb (Croatian: Kulturno informativni centar), believed that its construction was driven by the Cold War tensions and carried out in secret with some documents concerning the tunnel not having been released by the Croatian Ministry of Defence as of July 2016.

[11] A police report from around 1950 stated that squatters used the edifice for warmth and shelter from elements, as well as a hideout and a meeting place.

[4] The Yugoslav Government's lack of transparency regarding the tunnel led to the rise of a number of urban legends, including the purported existence of walled-off corridors leading towards the Croatian Parliament palace on St. Mark's Square (in the centre of Gornji Grad), and towards Zagreb Observatory (the northernmost point of the neighbourhood)[11] and on to Gupčeva Zvijezda.

Proposals included a "museum of senses", and a lift to allow people to reach Gornji Grad from the Tuškanac parking garage without climbing the steep hill on foot.

[8][20][6] The execution of the renovation was criticised for not following safety precautions; the tunnel was said to be damp and to lack smoke detectors, fire doors, sprinklers, or a mechanical ventilation system, and the fire escape route was problematic because two exits were narrowed to allow space for toilets.

[6] The tunnel complex was also used as a location in the pilot episode of the CBS TV series "FBI: International", broadcast 21 September 2021.