It's the car that's tilted, yet...
A study in Psychological Science details an illusion riders can experience when riding the Peak Tramway, a train which travels up and down a steep slope on Hong Kong Island.
Said lead researcher Chia-huei Tseng:
"On one trip, I noticed that the city's skyscrapers next to the tram started to appear very tilted, as if they were falling, which anyone with common sense knows is impossible... The gasps of the other passengers told me I wasn't the only one seeing it."Researchers discovered that the illusion seems to be enhanced by the window frames and other details inside the train car, and even when they modified those details, the illusion continued.
It seems that, in this illusion, an observer's sense of sight predominates over any other sensory cue, and even overrides a very obvious fact: buildings can't tilt like that.
Take a look at this video to see the illusion yourself (It appears within the time-frame of 1:40 - 2:35.)
Hong Kong Peak Tram
- Hong Kong skyscrapers appear to fall in real-world illusion, Science Codex>>
- Article abstract: Falling Skyscrapers. When Cross-Modal Perception of Verticality Fails, Psychological Science>>