Six thousand traditional Moroccan artisans worked for five years to create the abundant and beautiful mosaics, stone and marble floors and columns, sculpted plaster moldings, and carved and painted wood ceilings. The exterior surfaces of the mosque display titanium, bronze, and granite finishes. It is ornamented with pale blue marble and Zellige tilework. A particular feature in the mosque is that all structures are made of reinforced cement concrete and all decorations are of traditional Moroccan design. The construction work involved engagement of 35,000 workers and working of over 50 million hours. The mosque has capacity to accommodate 25,000 devotees for prayers in the main hall and another 80,000 in the plaza squares around it. Notable architectural features include the conspicuous columns, the horseshoe arches, and the innumerable muqarnas embellishing the ceilings. The dome, arches and walls give a grand ambiance to the mosque. The first-class sound system is discreetly hidden. The ablution room and a vast public hammam are in the basement, with its own entrance. Tadelakt, a plastering technique which adds egg yolks and black soap into mixed plaster, was used in the hammam baths. The building blends Islamic architecture and Moroccan elements, and reflects Moorish influences, while featuring an urban design. It displays elements found in other Moroccan buildings such as the unfinished mosque in Rabat and the Koutoubia Mosque in Marrakesh. There are features from an old Roman fort converted into the tomb of King Mohammed V of Rabat. Other elements come from the Tour Hassan Mosque, the Dome of the Rock (also known as Qubbat al Sakhra 688–692 AD), the Great Mosque of Madina (705–710 AD), Kairouan Mosque in Tunisia (663 AD), the Great Mosque of Damascus (705–715 AD), the Great Mosque of Cordoba (785–786 AD), Quarawiyyin Mosque (956 and 1135 AD) in Morocco, the Great Mosque of Tlemcen (1136), and Djamaa el Kebir (1096). Its layout is known as the basilican plan, which is different from the common practice of a T shaped plan adopted in many North African countries. The qibla wall is perpendicular to the naves which is said to be an unconventional layout, given that it is customary for the rows of worshipers facing Mecca to be as wide as possible rather than extend farther back (Halod and Khan 1997, 61).