Mohammed Ali mosque, Egypt, 10 Piastres

Though certainly not one of the most ancient mosques in Cairo, nor even one of the most historic, because of its grandeur and its location in the Citadel, the Mosque of Muhammad Ali is the most popular Islamic mosque among tourists.

This mosque is also sometimes referred to as the Alabaster Mosque due to its extensive use of that stone on some of the exterior walls and other surfaces. Sometimes it is popularly known as al-qal'a, meaning citadel, and thus confused with the fortress in which it is located.

Text Source: Tour Egypt