I want to take a look on church from the view of a musician: Since a few month I practice to go to a protestantic church on sunday and besides all questions about religion and belief a visitation of any church can fill your ears with many musical impressions. When you go in your attention is first catched by the wonderful acoustics (in case you are in a church with wonderful acoustics) and your exitement is raised by whispers and coughs until the mighty organ throws the first chords into the space. If you can listen to a serious organist, you are welcomed with a serious work and the organist will not only present something from the baroque-period. Perhaps you can listen to a work of Max Reger or Louis Vierne, or perhaps more modern like Olivier Messiean or Paul Hindemith. Depending on the acoustics the organ merges more or less with the room and it can be difficult to follow the movements of all single voices, but on the other hand organ and room merge and become something else. It is very interesting to listen carefully to the different voices and to the overall sound and to think over the possibilities of this impressing instrument.
Then the mass starts and during the celebration you sing sometimes together with the other people. Every song is introduced by the organ and again you can admire something, if the organist is a professional (as in my case): He or she can show a lot of different musical styles and periods during one single song or during a few songs. Starting with the introduction, which can be pentatonic, or chromatic, or romantic, or atonal, the accompaniment of the singers can be used by the organist as a complicated work of variations showing lots of different styles and lots of musical times and periods. While listening to these in the best case well conceived accompaniments you have to sing and you can train to be in tune with the organ and to highlite the right words. Sometimes the songs are not easy to sing also for a musician and I wonder sometimes, how the community manage it together.
If you are lucky you participate in a music-mass and you can admire a choir, or a choir together with a small orchestra, or another combination. Sometimes you also sing the liturgy together with the priest. But all in all when it ends your mind and ears are full of music and impressions, you have learned a lot, and you are thankful for another concert, which costs only a freely-given something at the exit.