Danish architecture studio EFFEKT has built a helical tower that invites you to climb up above the treetops of the Gisselfeld Klosters Forest in Denmark.

The 45-metre-high tower forms part of Denmark's largest climbing park, Camp Adventure, located an hour's drive south of Copenhagen.

It is the culmination of a 900-metre-long woodland walkway that weaves between a series of climbing courses, offering visitors a 360-degree view over the trees, hills, lakes and meadows that make up the natural landscape.

"Nature provides the real experience," explained Tue Foged, one of the two founders of Copenhagen-based EFFEKT.

"We just made it more accessible and offered a series of new and alternate perspectives."

The structure has an hourglass shape, defined by the changing curvature of the spiralling ramp.

This is supported by an external framework of crisscrossing diagonal columns that stretch all the way up from the ground to the top.

Structural elements are all made from weathering steel, which gives the building a rust orange colour.

By contrast, the walkway is made from boards of locally sourced oak, helping it to blend with its setting amongst oak, pine, beech and birch trees.

Its gentle incline means that, unlike many similar experiences, it is also accessible to wheelchair and pushchair users.

"The tower is shaped to enhance the experience of the visitor, shunning the typical cylindrical shape in favour of a curved profile with a slender waist and enlarged base and crown," said Foged.

"This allows for better contact to the forest canopy moving up through the tower."

The tower's top platform is 135 metres above sea level, making it the highest point anywhere in Zealand, according to EFFEKT.

The architecture studio claims that, on a clear day, it is possible to see Copenhagen and Malmø to the north.

EFFEKT first unveiled its design for the Camp Adventure tower in 2017, and has documented its construction in a series of drone films.

It is among a series of projects by the studio that embrace sports and other outdoor activities. It recently completed a conversion of an old windmill factory into a skatepark and has also designed a street sports centre in an old train engine depot.

The tower and boardwalk opened to the public at the end of March and welcomed more than 2,500 visitors on its first day.

Danish prime minister Lars Løkke Rasmussen, who cut the ribbon at the project's opening, said he was breath-taken.

"It is a magnificent project. Nothing less," he said. "The tower is beautiful on its own and could be placed literally anywhere. But here it is – in the middle of the forest surrounded by trees inside and out."

See more examples of spiral architecture. Photography is by Rasmus Hjortshoj.

Project credits:

Architect: EFFEKT
Structural engineer: Arup
Contractor: Levi Jensen