Drammen Spiral

The Drammen Spiral (Norwegian : "Spiralen Drammen") is a tunnel near Drammen, Norway.
Tunnel characteristics.
The tunnel is long and in the shape of a helix, with six rising circles, in the same style as a multi-storey parking lot. Each rotation of the helix rises , with a diameter of . The tunnel emerges at a summit above the town on Skansen Ridge, where there are parking facilities and a cafe.
Tunnel usage.
From the summit, tourists can walk in the "Drammensmarka", the forest area surrounding Drammen. There is a road toll levied for use of the tunnel, which for cars as of 2020 was NOK 35, paid as a parking fee at the top. The maximum height for vehicles is . Pedestrians may not use the tunnel: instead there is a gravelled zigzag track up the hillside with seats and viewpoints.
History.
The tunnel was proposed after concern was raised that quarrying was beginning to disfigure the local landscape. The community decided to tunnel for stone as an alternative, creating a tourist attraction as a by-product. Construction started in 1953 upon closure of the quarries. Rock excavated for the tunnel was crushed and used to make a harbour embankment in the city, while stone was used in concrete. The tunnel was opened for traffic in 1961 by King Olav V.
In 2020, the tunnel went through extensive renovation and was partly closed. It was officially reopened on Dec 12 2020.