Temppeliaukio Rock Church, Töölö, Helsinki, Finland

The interior was excavated and built into the rock but is bathed in natural light entering through the glazed dome. The church is used frequently as a concert venue due to its excellent acoustics. The acoustic quality is ensured by the rough, virtually unworked rock surfaces. Leaving the interior surfaces of the church exposed was not something that was in the original plans for the church. Conductor Paavo Berglund told the brothers of his experiences in the best music halls, and the acoustical engineer Mauri Parjo set out requirements for the wall surfaces. The architect brothers discovered that they could fulfill all the requirements by realising their own idea of leaving the rock walls exposed in the Church Hall. This idea the brothers already had when planning the competition entry, but they had been afraid to present it thinking it too radical for the competition jury.
The Temppeliaukio church is one of the most popular tourist attractions in the city; half a million people visit it annually. The stone-hewn church is located in the heart of Helsinki. Maintaining the original character of the square is the fundamental concept behind the building. The idiosyncratic choice of form has made it a favorite with professionals and aficionados of architecture.
The church furnishings were designed by the architects. Organ builder Veikko Virtanen manufactured the church organ, which has 43 stops.
There are no bells at the church; a recording of bells composed by Taneli Kuusisto is played via loudspeakers on the exterior wall.