Between 1959 and 1961, Claude Parent collaborated on several occasions with Yves Klein on “air architecture” projects – basic experiments that would have a profound impact on his subsequent research on space. Following the artist’s unexpected death in 1962, his mother and her husband called on Parent to undertake a project for a memorial to their son at Saint-Paul de Vence (1964-65). The architectural organization of this concrete memorial is intended to embody the cosmic quest of a “painter of space”. Parent designed a course on three levels, choosing open plans and pure volumes, like these “cylindrical aiming elements”. Three of them seem to “levitate” above a square plinth, placing the elements (air, earth, water, fire...) and space (verticality, horizontality, oblique) in tension. The void is the force structuring the architecture, “calling upon the immaterial, the monochrome and the atmospheric”. Thrust into the ground, the fourth cylinder introduces a telluric principle; it leads to a “crypt” containing the Monogold, a series of monochromes with alchemic properties made by Klein, for whom the color of gold symbolized the accession to immateriality. Thus, this path of spiritual liberation sublimates the conflict between the multiplicity of perceptions on the outside and the opaque depth of the shapeless buried space. Claude Parent’s proposal is nourished here by the idea of “crypticity” developed by Paul Virilio, one which together they would implement during this same period in the Church of Sainte-Bernadette du Banlay (Nevers, 1963-66). Here, as in Nevers, the cryptic space embodies the dialectical encounter of sky and earth.