The Sanctuary of Fátima (Portugal) is a world known Catholic pilgrimage center since 1917 when Holy Mary appeared to three children. The project for the 9,000-seat church of the Most Holy Trinity is in its final stage designed by the Greek architect A. Tombazis. This mega church will have a volume of about 130,000 m3 and an average height of 15 m with two modes of use configurations (3,000 and
... [Show full abstract] 9,000 seats). Its seating capacity will make it the largest church in Portugal and one of the largest Roman Catholic churches in the world. This religious complex will also house four smaller churches and the construction will end on 2005. This paper presents and discusses the acoustical requirements set by the Owner's acoustical consultant as well as the main design considerations regarding Reverberation Time, RASTI, background noise, etc.