The Porch-Tower The Porch-Tower, with its impressive architectural mass, is an exceptional and unusual edifice. The power and number of its columns reveal the ambitiousness of this project. At ground level, the four pillars of the central part, without pedestals, divide the space into nine squares of roughly equal size with vaulted roofs and connected by transverse arches. The east side, originally like the others, was transformed during its attachment to the nave. The architecture of the porch-tower evokes the celestial city, the new Jerusalem, described by St. John in Chapter 21 of the Book of Revelations, the last book of the Bible. "It forms a square, its length equal to its breadth. It has twelve doors, three to the east, three to the north, three to the south, three to the west and they are never closed since this place knows neither day nor night…". The capitals also illustrate the book of St. John and his prophesies on the destiny of the world