Historically, the urban situation in the cities and towns of Persia and Algeria was highly specific. The hot dry climate contributed to a street network, which was protected from the sun as much as possible. Climate conditions determined the appearance of houses with flat roofs, small windows and white walls. The entire urban planning system had the main centre - the city (town) mosque. There were smaller mosques in the structure of residential areas, densely surrounded by houses. Just as under the influence of climate a certain type of residential building took shape, these same factors formed a characteristic type of mosque in the housing environment. Globalist trends have affected even such a conservative sphere as Islamic religious architecture, as it gradually toned down striking regional features, which is explained by the typicality of modern building materials and structures and the international activity of various architectural and construction firms in different corners of the world. Over the centuries, two opposing images of the mosque have emerged - the pointedly magnificent Persian and the fortress-type of Maghreb (typical for Algeria) types. This paper reviews how specific climatic conditions and historical processes influenced the use of building materials, structures and decoration in the mosques of Persia’s and Algeria’s different regions. Today we observe an erosion of regional features in the form and layout of modern mosques, which are analysed on the basis of the examples given. On the basis of a comparison of authentic mosques and erected by foreigners, it is proved how local features are gradually being eliminated and what this leads to.