The Palazzo Spada in Rome, built in 1638 by Francesco Boromini, is an illuminating example of how perspective can be used to deceive the eyes.
Fig. 35 – A view of the Palazzo Spada in Rome.
From the view in Fig. 35, it appears as if the pathway is rather long, leading to a statue at the end. The statue is about three-quarters the height of the distant doorway. However, when a person who has the same height as the statue stands at the near doorway, we find that she is only about a quarter the height of the near doorway (Fig. 36).
Fig. 36 – Comparing the heights of the doorways.
This puzzling phenomenon can only be explained if one realizes that the two doorways are of vastly differing heights. However, as the tunnel seems to be constructed in perfect perspective, we are tricked into believing that both doorways are of the same height.