For architecture, building sites represent the moment of truth, they are the place were the architect’s dream comes true, thanks to the contribution of engineers and workers capable of embodying and materialising the project. Work in the building site of the Tor Tre Teste church in Rome has been proceeding feverishly for several months and, day after day, a church complex on which a lot has been staked is taking shape. The first party to invest on the project was of course the consigner, the Roman Vicariate, that bravely decided to realise a church so far away from the conventional mould; but we also have all the firms involved in the practical realisation of this work. Besides, the objective of this church is to reconnect an isolated district to the urban structure of Rome, as well as laying emphasis on the willingness of the Church to regain possession of its role as artistic promoter, which, after a millenary tradition, had been weakening over the last two centuries, aiming at a research work capable of harmonising the present with the timeless values of man and religiousness. Among the many projects submitted, the one which proved closest to the implicit and explicit requirements involved in this assignment was certainly Richard Meier’s, which suggests a powerfully symbolic and immediately perceivable architectural style: the sail, the light, the surrounding opening, the purity. Morality and transparency, protection and permeability, isolation and unanimity are indeed the strong features characterising this work. The outside is as full of atmosphere as the inside: three isolated sails in parallel, chiselled with gradins, swollen with wind, enclose a longitudinal space defined by a long blind wall. Light literally floods in from the lateral facades, entirely in glazed windows, and from the upper interstices between the sails and the wall. Internally, the space is defined by alternating blind and translucid broad surfaces. The sails, placed side by side, are internally ripped by large portals decreasing towards the outside, expanding the space of the hall and conveying depth and secluded areas. Indeed, even though, as in all other projects, attention has been paid to volumetry, architectonic details and colour, the aspect which is most appreciated in this case is in fact this complex volumetry, realized by means of curves and sphere sections. The human eye is used to continuously perceive straight lines and angles of 90 degrees, we see them everywhere and all the time, whereas the surface which will result from this project is truly different, conveying the impression of a sail, which seems to swell with wind. However, it should be stressed that Meier has never mentioned the word “sails”, which is in fact somebody else’s later definition (he called them “shells”); indeed, his purpose was to create three large spherical surfaces to produce an enveloping space, a sign of welcome powerfully illuminated by the light pouring from above, modelling itself upon the curving walls and gradually changing into shadows. Besides, sails have always conveyed to people’s imagination the idea of a voyage towards a new world, and possibly in the new millennium the metaphor of the voyage fits in with the Church, which cannot and does not want to remain idle. The true problem, as it often happens, has been that of switching from a symbol to reality, and therefore getting the sails to stand up. The designers working on the structures have indeed faced unprecedented construction theory problems, as well as practical problems, in the laboratory, in the factory and on site. The first serious considerations as to how to proceed arose after being informed about how the American structuralists, who acted as Meier’s advisors, indented to realise the church. For the spherical walls, they had proposed an inner metal structure to support concrete slabs, which were to be subsequently plastered. Apart from the unusualness of this technique, compared to the Italian building tradition, this solution had immediately appeared hardly feasible, owing both to the deformability of the structure and to the heterogeneity of materials, which could not be that easily “stuck” together. But the new idea was to construct the sails with large and heavy prefabricated and post-stretched white concrete panels, displaying a double-bend geometry, which certainly represents an unprecedented construction system. This procedure was selected among other construction processes, as it recalled the ancient Roman stonework technique, involving the use of large travertine blocks, which in two thousand years has withstood the test of time, thus avoiding today’s sophisticated techniques, with sails in sheet metal, which would only have a short life. On the other hand, this church, besides being the symbol of the Jubilee, will also carry authority because of its unique scientific value. This church goes beyond the congregation’s interest, as it involves all Roman citizens, who still believe architecture to be part of the city’s treasures; this is why it will become a Church Triumphant, and part of the huge cultural heritage made up by the many churches triumphant delivered to history, without which it would be difficult to conceive Rome as it is today, let alone other towns. Besides, the Gothic style (for instance) was also invented by the Church, because there were no other structures that could adequately represent the theological notions and worship requirements of the time; however, that language later became part of civil architecture as well. And in the second part of the last century, when the first industrial plants started to appear, the Gothic structural scheme was revisited, as it proved the most suitable to cover vast spaces. Therefore, once again the Church offers itself as a source of inspiration for new techniques and challenges, involving both design and realisation, but always bearing in mind the ultimate aim in the construction of a new Church. And this new challenge has been taken up by all the parties contributing to the project, by devising, as we have seen, unprecedented techniques and materials, which however are bound to last. r.p.