This weathering steel staircase by engineering studio Close to Bone cantilevers off a hill in Flanders, forming an observation tower overlooking rolling farmland and the Kabouterbos forest (+ slideshow).

Standing unsupported at almost 11.5 metres tall, the staircase "floats" above its picturesque setting in the the Tielt-Winge municipality.

The structure known as Vlooyberg Tower was designed by the Belgian studio to replace an existing wooden lookout post on the site, which was burnt by vandals.

To prevent further acts of arson, the new tower is engineered completely from metal. It comprises several galvanised steel sections that are clad in sheets of pre-rusted metal, known as weathering steel.

"The story of the Tielt stairway tower goes back a long way. For many years, the hill to the west of the Vlooiberg was adorned by a wooden lookout tower about four meters in height," explained Close to Bone.

"Aside from the all the youth of Tielt, unfortunately this tower also attracted vandals who irreparably damaged it by setting it on fire," it continued.

"Heated debates followed, and the municipality finally decided to replace the small wooden tower with a new, monumental object that would be able to withstand the ravages of time."

Weathering steel has become a popular material choice for landmark architecture, as its aged appearance fits in well in natural settings. NEXT Architects designed a curling rusting steel walkway for a grassy peak in near Rotterdam, while Rintala Eggertsson Architects used the material for a river crossing in Norway.

The rusty orange colouring of Vlooyberg Tower is a reference to the red-brown ironstone found in the region.

A viewing platform is set 10 metres above the ground at the summit of the staircase, where small peepholes in the tall balustrades frame views over the pastoral landscape.

Weighing in at 12 tonnes, the tower is at "war against its own weight" according to the engineers, who manually calculated the forces acting in each element of the staircase to define its form and dimensions.

The railings serve as structural beams to keep the staircase upright, while two dampers help to prevent the staircase from vibrating under foot. The whole structure was prefabricated and assembled on site over the course of half a day.

"As a landmark with strong iconic value, the Vlooyberg Tower literally and figuratively raises the profile of the beautiful region around Tielt-Winge," said the team.

"Natives of Tielt, chance passers-by and fans of modern architecture all greatly enjoy this intriguing monument."