The Altun Alem Mosque is built in Novi Pazar between 1518-1528. Ac-cording to the foundation charter of the mosque, patron of the mosque is Musli-hudin Abdul Gani-Muezzin Hoja el Medini. The same patron in the equal period built almost same, but bigger mosque in Skopje, Macedonia. The Architectural plan of the Altun Alem’s prayer hall is square, on the left side of the northwest wall there is the main door of the mosque and in front of this wall, there is a narthex covered with two domes. While comparing this architectural plan, with mosques built through the Balkans in a 16th century, we can notice that in this period mosques that are built, are mainly built in a typical Classical Ottoman Architectural style of the mosques. This notation is not the case with the Altun Alem Mosque, unlike with another mosques, the Altun Alem Mosque is built in Early Ottoman Architectural style of the mosques. Taking into account that this is not first example of using this kind of architectural plan, we can conclude that special features of the architectural plan of the Altun Alem Mosque is not exactly in its architectural plan, actually, its specification is in a period when it is built. Considering that the period when the mosque was built was the period of the reign of Sultan Suleiman I, the period of the rise of the Ottoman Empire, it is quite surprising to encounter this architectural type of mosque. Considering all these facts, it is easy to realize that the reason for building this kind of mosque in the 16th century in Novi Pazar, was much more than we can see at first. Altun Alem Mosque as a pearl hidden in shell, today proudly represents a rare example of Ottoman architecture in Serbia.