This article tries to reveal, through the study of the works and writings of Mies van der Rohe, the "imaginary universe" that precedes his creative activity and on which it is based, in order to learn more not only about his work, but also about that personal world, that world of ideas, from which it arises, so that we are able to better understand the origin and development of his creative process. Mies is an intimate and patient architect. He spent years shaping that imaginary world in which he carried out his creative activity. That imaginary world was incubated in the immaterial space of temporary exhibitions. Many of his projects can only be understood in relation to others or as part of a series of self-absorbed relationships and themes of his own that he intertwined with his own biography. Mies made through his architecture a veritable exercise of projection. His statement that the development of his architecture came from within could become significant and be sufficient to explain certain aspects of his work, especially of the one in which he felt more comfortable and worked more freely, such as the design of his exhibition spaces.