In the centre of the oasis is the old kasbah or citadel.
The city consists of two parts; the modern French town, built on the level ground by the seashore, and the ancient city of the deys, which climbs the steep hill behind the modern town and is crowned by the kasbah or citadel, 400 ft.
The kasbah forms the apex of a triangle of which the quays form the base.
They often end in a cul-de-sac. The principal street is the rue de la Kasbah, which leads up to the citadel by 497 steps.
The public buildings of chief interest are the kasbah, the government offices (formerly the British consulate), the palaces of the governor-general and the archbishop - all these are fine Moorish houses; the "Grand" and the "New" Mosques, the Roman Catholic cathedral of St Philippe, the church of the Holy Trinity (Church of England), and the Bibliotheque Nationale d'Alger - a Turkish palace built in 1799-1800.
The kasbah was begun in 1516 on the site of an older building, and served as the palace of the deys until the French conquest.
The Arabic invasion at the end of the 7th century destroyed the Byzantine towns, and the place became the haunt of pirates, protected by the Kasbah (citadel); it was built on the substructions of the Punic, Roman and Byzantine acropolis, and is used by the French for military purposes.
The town consists of a European quarter, with streets regularly laid out and fine houses, and the Arab town, with its kasbah or citadel, and tower-flanked walls pierced by three gates.
The Kasbah (citadel) stands on a hill at the north-east of the town.
Bona (Arabic annaba, " the city of jujube trees"), which has passed through many vicissitudes, was built by the Arabs, and was for centuries a possession of the rulers of Tunis, who built the Kasbah in 1300.
The town was occupied by the French for a few months in 1830 and reoccupied in 1832, when Captains Armandy and Yusuf with a small force of marines seized the Kasbah and held it for some months until help arrived.
The city, which was formerly strongly fortified, is built in the shape of an amphitheatre, with the kasbah, or citadel, at its highest point.
That to the right, the Rue de la Kasbah, opens into a small square (Suk-el-Islam or Place de ]a Kasbah), on the left of which is the Dar-el-Bey (palace of the bey), while beyond it rise the walls of the citadel.
The kasbah, which forms the western side of the Suk-el-Islam, includes within the circuit of its walls a mosque built about A.D.
Of the ancient kasbah nothing but the walls remain, the old buildings having been demolished to make way for barracks for the French troops.
Besides being a fortress the kasbah formerly contained a palace of the beys, barracks for janissaries and bagnios for the Christian slaves.
Attacked Tunis, the Christians in the kasbah, said to number 10,000, rose against their keepers and helped to secure the victory of the emperor.
The Spaniards during their occupancy of Tunis strengthened the kasbah and built an aqueduct to supply it with water.
Immediately north of the kasbah are the buildings of the Sadiki College, and north of the college is the Palais de Justice, a building completed in 1901.
The native city to the north of the Rue de la Kasbah includes the Jewish quarter and the synagogue.
South of the Rue de la Kasbah is the bazaar quarter.
Traces of the Spanish occupation from1610-1689are to be seen in the towers whose names are given by Tissot as those of St Stephen, St James and that of the Jews, with the Castle of Our Lady of Europe, now the kasbah or citadel.
The place du Palais, in which are the palace of the governor and the cathedral, and the kasbah (citadel) are west of the rue de France, as is likewise the place Negrier, containing the law courts.
The kasbah, which occupies the northern corner of the city, dates from Roman times, and preserves in its more modern portions numerous remains of other Roman edifices.
High, discovered in the kasbah in 1858.
The kasbah (citadel) or Château Vieux, usedjfor military purposes, lies S.W.
On the hills behind the kasbah are Fort St Gregoire, a votive chapel commemorative of the cholera of 1849, and Fort Santa Cruz, crowning at a height of 13 12 ft.
Fort St Philippe, south of the kasbah, replaces the old Castle of the Saints of the Spaniards.