Set on a mountain summit more than 3,000 metres above sea level, Herzog & de Meuron's Titilis 3020 station and restaurants will cantilever out over the Swiss Alps.
Two steel volumes will be inserted crosswise into an existing antenna tower to create a bar and restaurant with panoramic views, while a new station will be built around the existing cable car system.
"Our project on the Titlis belongs to a new generation of alpine architecture that aims to do justice to the breathtaking landscape by ensuring a corresponding architectural experience of the kind now familiar to us in our cities," said Herzog & de Meuron.
"The Titlis project articulates an unstoppable process that is transforming Switzerland."
The Basel-based firm was commissioned to renovate the buildings on top of Klein Titlis, a mountain in the Engelberg skiing region. Over one million visitors come up the mountain each year, with up to 2,000 a day at peak times.
Herzog & de Meuron surveyed the existing gondala summit station, which was built in 1967 and has undergone several refurbishments. The architects discovered the current building's load-bearing structure wouldn't accommodate the changes needed to fix overcrowding issues in the station.
The existing gondala will be encased in the new steel and glass crystalline horizontal building. It's low-lying form will make it appear as though it is pushing out of the Titlis glacier like a "flat crystal growing out of the mountain" said the architect.
Visitors will exit the gondala onto a concourse level with the glacier, with a sloping walkway leading to escalators and the exit. The previously obstructed view west over the mountains will be visable from a walkway below the cable car station. A selection of restaurants, which will be able to seat 550 people, will be located on the top floor of the station.
Herzog & de Meuron will also renovate the underground tunnel that connects the station to the antenna tower. An "ice grotto" will allow visitors to view the glacier from the inside.
The 50-metre-high beam antenna tower was built from industrial steel by the Swiss Post in 1980s. It was bought by Titlis railways, when new technology rendered it mostly obsolete, although the antenna remains in use.
Two steel intersecting beams will turn the infrastructure tower into a landmark attraction. Stairs and lifts will run up the four vertical supports, reinforcing the structure.
A lobby will be carved into the existing concrete base, giving direct access to the tower from the glacier. Up in the new levels, a bar, restaurant and lounge can seat 330 people with views south over the Alps and of Switzerland to the north.
Herzog & de Meuron, founded by Jacques Herzog and Pierre de Meuron in 1978, has previously built a mountaintop restaurant that wrapped around a cable car station on the Chäserrugg mountain. The architects used spruce, creating a building that aimed to reference alpine architecture without becoming kitsch.