Local rulers had long overlooked the strategic value of the hill above the city, but, within a few years of his arrival in 1168, Salah al-Din al-Ayyub began creating defense plans with the Citadel at their center. He and his successors built an impenetrable bastion using the most advanced construction techniques of the age, and, for the next 700 years, Egypt was ruled from this hill. Nothing remains of the original complex except a part of the Ayyubid walls—33 feet (10 meters) tall and 10 feet (3 meters) thick—and the Bir Youssef (Youssef Well), which was dug 285 feet (87 meters) straight into solid rock to reach the water table and is still considered an engineering marvel.
In the 1330s, most of the Ayyubid buildings were replaced by Mamluk structures. After assuming power in 1805, Muhammad Ali had all the Mamluk buildings razed and the complex entirely rebuilt. Only the green-domed mosque and a fragment of the Qasr al-Ablaq (Striped Palace) remain.
For more than 150 years, the Mosque of Muhammad Ali has dominated the City's skyline. Although Ottoman law prohibited anyone but the sultan from building a mosque with more than one minaret, this mosque has two, one of the first indications that Muhammad Ali wouldn't remain submissive to Istanbul. Note the spacious courtyard's gilded clock tower, which was provided by King Louis Philippe in exchange for the obelisk that stands in Paris. It’s fair to say that the French got the better end of the bargain: the clock has never worked.
Behind Muhammad Ali stands the Mosque of al-Nasir Muhammad, a Mamluk work of art with beautifully crafted masonry, elegant proportions, and a minaret featuring ornate but refined details. Ottomans took much of the original interior decoration to Istanbul, but the space is nevertheless impressive. The courtyard's supporting columns were collected from various sources; several are pharaonic.
Across from al-Nasir's entrance is the National Police Museum, worth a quick visit to see the exhibition on Egypt's political assassinations and to enjoy the spectacular view from the courtyard. The enclosure directly below, gated by Bab al-Azab, is where Muhammad Ali wrested control from the Mamluk chiefs. (He invited them to a banquet and had them ambushed by a battalion, ending their dominion in Egypt and eliminating all internal opposition in a single stroke.) To the northwest of al-Nasir, the gate known as Bab al-Qulla opens to the Qusur al-Harem (Harem Palace), now the site of the National Military Museum, with somewhat interesting displays of uniforms and weaponry.
Farther west, the Carriage Museum, the dining hall of British officers stationed at the Citadel in the early 20th century, now houses eight conveyances used by Egypt's last royal dynasty (1805–1952). In the northwest part of the Citadel is the rarely visited Sulayman Pasha Mosque built in 1528. While its plan is entirely a product of Istanbul, the sparse stone decoration shows traces of Mamluk influence.
Before leaving the Citadel, pass by the Qasr al-Gawhara (Jewel Palace), where Muhammad Ali received guests. It's now a museum displaying the royal family's extravagance and preference for early 19th-century French style.
