The challenge takes place at a unique location: KTH’s Reactor Hall.

The Reactor Hall hosted R1, the first nuclear reactor of Sweden. R1 was a research reactor located at the KTH campus at Valhallavägen in central Stockholm, in the rock beneath the current-day Q buildings.

The reactor was active from July 13, 1954 to June 6, 1970. The reactor was later dismantled, and there is nothing left of it today; the reactor hall however still exists.

After being dismantled, the hall that hosted R1 was deemed safe and is now used for events like art exhibitions, concerts and music videos due to its interesting aesthetic and acoustics. In 2016, the reactor hall was used to film the music video for Alan Walker’s song Faded (Restrung)