In the concept of space devoted to places of religious worship in the 20th century there were changes that lowered the rank of the oldest traditions. In addition to understanding a space in which a temple was erected as a “holy place”, the concepts of “sacred space” and “area of transcendence” emerged. The most enduring custom of locating a sanctuary was linked to the necessity of commemorating a place of a direct manifestation of a divine being, as described in the Book of Genesis (Genesis 28: 16–19), where the Patriarch Jacob dedicated a stone that became the instrument of God’s revelation and made it the prototype temple. A similar custom was also characteristic of pagan religions, but already in the fourth century it was incorporated into the Christian rite. The practice of shaping a building as a place directly connected with a holy being was also consolidated by the rule, characteristic of the beginning of the Christian architecture, of consecrating a temple only after placing the remains of the saints in it. In Christianity of the West, the rejection of the concept of the sanctity of a church building was rare, but it became evident in the architecture of Protestant denominations. In the Catholic and Orthodox trends, the aspirations to emphasize the holiness of a cult building were manifested by separating it from the secular space and by distinguishing it with artistic forms and symbols. As regards the places of worship in the second half of the 20th century, the term “sacral architecture” and sometimes also “sacral space” became popular. It should be noted, however, that the concept of sacredness comes from religious studies and presupposes the functioning of sacrum as the universal holiness that precedes the divinity of a particular religion. The concept of sacrum has gained enormous importance in the 20th century, although it was inconsistent with the theological foundations of Christianity. The consequence of the search for the holiness over specific religious denominations was to reduce it to the essential or primordial values. It brought such an understanding closer to the aspirations characteristic of the art of avant-garde modernism. It can be said that any tendencies of the architecture of radical modernism, based on the simplification of forms, especially their geometrisation or archaization, are particularly suitable for the creation of religious settings for cult sites, where the inclinations with regard to the conception of sacrum dominated the Christian content. A prominent example of such situation is the chapel built by Mies van der Rohe at the Illinois Institute of Technology campus in Chicago. Some of the church buildings of the late 20th and early 21st centuries, built for the needs of Christian churches in the West, express the reflection that the essence of human existence is the constant pursuit of transgressing the intellectual or spiritual status quo. Within this concept, transcendence was not understood as a divine being, but as a process of transgression directed at infinity and giving a sense and a value to an individual’s life. In this situation, the architecture erected for the needs of particular denominations and created by religiously indifferent designers became a space that reminds about other human destiny than merely rational. In objects of this kind it was shown that pure efficiency does not exhaust the most important modalities of human existence. The ideological content of the concept of transcendence was not in line with the traditional message of the Christian religion, but when they were enabled to find their expression in new church buildings, they included their seemingly religiously indifferent followers in the long chain of searchers of the final dimensions of human fate