Decorations in Mosques and Churches

Have you ever wondered about the main differences in decoration between the mosques and the churches? There are some common elements such as using stained glass, light, and so on. Actually, there are also big differences between them:

In churches (of course some churches such as Protestant churches are excluded), paintings, icons, and images are the most important elements of decoration inside the church. Those paintings and images are related to biblical stories and of course, this makes the church like a museum.

Images, icons, or statues are proscribed in Islam (it is a controversial subject in some ways and I am not qualified to talk about it). The reason for prescribing them is eradicating idolatry and cut off any connection with that. A few elements such as calligraphy and geometrical shapes and patterns are the most important elements of decorations inside the mosques. 

Calligraphy: As for the Muslims Quran is a miracle; a book that was written down in Arabic after the revelation and it is said that calligraphy is the most important art in Islam. So calligraphy was developed and the Muslims put it to good use for decorating the mosques; almost in every mosque you can see the art of calligraphy (often verses of Quran).

Geometrical shapes and patterns are another important element of decorations in mosques. These patterns are emblematic and beautiful and of course, they show unity and pantheism and of course, monotheism.

This was mostly from my own observation in mosques and churches in Iran and it's not complete and can not be generalized.