You are looking at one of the four bathrooms in the PPDG penthouse designed by Hernandez Silva Arquitectos. Located in Guadalajara, Mexico, the original 15-storey building was constructed in the 1970s. The original plans for the building included a second elevator that was never installed (even though the elevator shaft itself was built).

With the penthouse on the top floor, Hernandez Silva Arquitectos decided to expose the shaft via a glass floor that looks down all 15 storeys. It just so happens that the powder room was directly above the shaft, making for one of the most memorable bathroom experience ever…
 
[Let me be inspired via Reddit]