After the Second World War, the Finnish sacral building faced a new era. The need for the new spaces was urgent due to the urbanization, the large number of children, the new parish activities, and the post war reconstruction of the country. Also, the architectural ideas altered, and modernization reached the sacral architecture – a quarter of a century later than in industrial or residential building. Alvar Aalto’s Vuoksenniska Church, completed in 1958, is regarded as a landmarking building in Finland. It started a new phase of modernish in sacral architecture. It also provided multiple functions for the parish use including modest indoor sports facility, lecture room, and canteen. The sacral character and architectural expression started to diminish in many cases as churches became merely parish centers, but not in Aalto’s innovative building. Despite the complex variety of uses the Church of the Three Crosses has a clear impression of a sacral building, articulated by the over 30-meter-tall campanile. The Church of the Three Crosses is considered Aalto’s response to the development of modern church architecture in central Europe and its significance can be compared to Le Corbuisier’s masterpiece the Notre-Dame-du-Haut in Ronchamp, France. Being simultaneously a pioneering achievement of modern architecture and a new step in the tradition of sacral architecture the Church is a key building in Alvar Aalto’s highly appreciated curriculum.