mosques: the holy cities
Recall that, as Islam spread throughout the known world, it spread as a conquering religio-political power. Even though the Muslims of the first century or two might be minorities, ruling over non-Muslim populations, they nonetheless left their architectural "footprints" on the cities over which they ruled. Mosques rose like great stone monuments.
Some of the earliest and most spectacular mosques are found in the three most holy cities of Islam: Mecca, Medina, and Jerusalem (where the Prophet was believed to have embarked on his mir'aj, his nighttime ascension to heaven).
The mosques in Medina and Mecca are much more than houses of prayer, they are monuments to the foundation of Islam. Below: first, the mosque that surrounds the ka'aba, the sacred shrine, the object of Islamic hajj (pilgrimage), and the orientation (qibla) of Islamic prayer; second, the mosque that has been built in Medina over the home and tomb of the Prophet Muhammad.
In Jerusalem, the "Dome of the Rock" (one of the oldest mosques in the world) stands on the top of the Temple Mount, where the Temple of the Jews once stood:
As the Temple did in antiquity, the Dome of the Rock dominates the skyline of Jerusalem.