An architectural steel sculpture, 'Seesicht Skulptur,' in Zug, Switzerland, is in a prominent location at the lakeshore (Rössliwiese) and takes visitors down a staircase giving them an astonishing view.

After five years of planning, the sculpture was handed over to the citizens of Zurg on May 30, 2015. The sculpture will remain there for 10 years and is open on a regular basis.

Description from https://www.zug-tourismus.ch/en/culture/sightseeing/roman-signer-lake-view

THE SCULPTURE, WHICH ONE CAN WALK ON, GIVES VISITORS A NEW VIEW OF REALITY.
The architectural steel sculpture, at a prominent location on the lakeshore (Rössliwiese), takes visitors down a staircase below the lake surface and gives them a view into the lake via a window.
After five years in planning, this sculpture was handed over to the citizens of Zug on May 30th, 2015. It will be there for ten years and open on a regular basis. In May 1990 the Kunsthaus Zug opened its doors – not only did a rich collection of extraordinary art pieces come together over the last 30 years, but in this time projects that stretched traditional ways of thinking were also displayed. For its 25-year anniversary in 2015, the Kunsthaus Zug realised the Seesicht Skulptur from the famous Swiss artist Roman Signer (*1938) on the Zug Promenade.