The story goes as follows:
Nearly a century after the construction of St. Peter's Basilica, Bernini (sculptor and architect, the author of many of Rome's fountains and designer of Barberini's Palace, among other things) was called upon by Pope Alexander VII to make further improvements to the church.
As he studied the Basilica from various angles and distances, it occurred to Bernini that he could not see the dome at all if he stood too close to the facade. This struck him as a major design flaw.
In order to rectify the situation without rebuilding the Basilica from the ground up, Bernini designed the now famous piazza in front of it, with a colonnade encircling it.
Thus, psychologically, the main entrance of the Basilica was "relocated" from the actual Basilica to the entrance of the piazza, where the dome was in full view, Bernini's idea being that the piazza served as some sort of anteroom of the Basilica.
This sounds awfully awkward and confusing unless illustrated by a picture:
How would you describe what Bernini did? What word, or words, would you use to get the point across without falling back on visual aids?
Bernini devised a ... what? ... [pretend? new, psychological?] entrance? The plaza's ... what? ... entrance? ... became the Basilica's new entrance? ...
There's a couple of words I'm missing here. I'm pretty sure they're fairly common, straight-forward ones, I just can't remember what they are.