Algiers sits on the Mediterranean coast where the Sahel hills meet the sea, approximately 36.7 degrees north latitude and 3.0 degrees east longitude. The city occupies roughly 363 square kilometers across a natural amphitheater that rises from the waterfront to elevations exceeding 400 meters in the southern districts. The Mediterranean forms the northern boundary, while the Mitidja plain extends south and west. The urban area contains an estimated 3.4 million residents within the city proper and approximately 5 million across the metropolitan region, making it Algeria's largest urban concentration and the ninth-largest city in the Arab world by population.
The Casbah forms the historic core of Algiers, a UNESCO World Heritage Site since 1992 covering approximately 50 hectares on the hillside above the port. This medina contains around 1,600 buildings constructed primarily between the 16th and 18th centuries during Ottoman rule, with settlement patterns dating to Phoenician occupation around the 3rd century BCE. The neighborhood's street network follows topographic contours, with passages as narrow as one meter connecting residential compounds built around interior courtyards. The Djamaa el Kebir, or Great Mosque of Algiers, stands at the Casbah's lower edge, with construction attributed to the Almoravid dynasty in 1097 CE, making it the oldest mosque in the capital and one of the oldest in North Africa. The minaret rises 27 meters and follows Zirid architectural conventions, with modifications added during Ottoman administration.
The French colonial period beginning in 1830 produced the quartier Haussmannien along the waterfront and extending southwest from the Casbah. This district features buildings in French Second Empire and Art Deco styles constructed primarily between 1850 and 1930, with wide boulevards arranged in a grid pattern contrasting with the Casbah's organic layout. The Grand Poste, completed in 1910, exemplifies neo-Moorish colonial architecture with a symmetrical facade measuring 70 meters across and incorporating decorative elements from Andalusian Islamic tradition. The cathedral of Notre Dame d'Afrique, constructed between 1858 and 1872, occupies a promontory 124 meters above sea level in the Bouzareah district north of the Casbah, with a dome reaching 75 meters height and interior mosaics covering approximately 400 square meters.
Algiers served as capital of the Regency of Algiers under Ottoman sovereignty from 1516 to 1830, functioning as a major Mediterranean port for corsair activity and trade. The population during this period fluctuated between 80,000 and 120,000 residents, making it among the largest cities in the Maghreb. The French conquest on July 5, 1830 began a 132-year colonial period during which Algiers became the administrative center of French Algeria. The city's population grew from approximately 30,000 in 1830 to 300,000 by 1954, with European settlers constituting roughly 65 percent of residents by the mid-20th century.
The Battle of Algiers between January and October 1957 centered on the Casbah, where National Liberation Front (FLN) operatives conducted an urban guerrilla campaign against French paratroopers under General Jacques Massu. The French military employed approximately 8,000 troops in the Casbah alone, conducting systematic searches of the neighborhood's estimated 80,000 residents. The conflict resulted in an estimated 3,000 Algerian deaths and the capture or elimination of the FLN's urban network, though the political costs to French colonial rule proved severe. Algeria achieved independence on July 5, 1962, and Algiers became capital of the new republic under President Ahmed Ben Bella.
The Martyrs' Memorial, or Maqam Echahid, opened on the 20th anniversary of independence in 1982 on a hill in the El Madania district. The monument stands 92 meters tall with three palm-leaf-shaped concrete structures surrounding a central flame, visible from most of the city and the Mediterranean approaches. The structure commemorates the estimated 1.5 million Algerian deaths during the War of Independence from 1954 to 1962. An underground museum beneath the memorial contains seven exhibition rooms covering 2,800 square meters, documenting the independence struggle through photographs, weapons, and personal effects of resistance fighters including Larbi Ben M'hidi and Hassiba Ben Bouali.
Houari Boumediene International Airport, located 20 kilometers east of the city center in Dar El Beïda, opened in 1924 as Maison Blanche Airport and received its current name in 1981. The facility handles approximately 9 million passengers annually and serves as the primary hub for Air Algérie, which operates direct flights to 28 international destinations across Europe, Africa, and the Middle East. The airport contains two terminals with a combined capacity of 12 million passengers, expanded in 2006 and 2019.
The Algiers Metro began operation in November 2011 as the first rapid transit system in North Africa, initially covering 9.2 kilometers with 10 stations between Tafourah in the Casbah and Haï El Badr in the southern suburbs. A one-way ticket costs 50 dinars, approximately 0.37 euros at 2024 exchange rates. Extension projects announced in 2015 proposed adding 11 kilometers and 14 stations, though construction timelines remain indefinite. The system operates from 5:30 AM to 8:00 PM daily, with trains running at 3 to 5-minute intervals during peak periods and carrying approximately 130,000 passengers per day.
The city's tramway network opened in May 2011, operating on standard gauge tracks covering 23.4 kilometers with 28 stops between Dergana in the east and Bordj El Kiffan on the coast. Daily ridership averages 100,000 passengers, with single-journey fares at 40 dinars. The tram operates from 5:00 AM to 10:00 PM, with frequencies of 6 to 8 minutes during peak hours. Cars manufactured by Alstom in France measure 32 meters long and accommodate 168 passengers with combined seating and standing capacity.
The University of Algiers, established in 1879 as a French colonial institution, occupies campuses across the metropolitan area with the central campus in Bab Ezzouar housing science and technology faculties. The institution enrolled approximately 120,000 students in 2023 across three successor universities created in 1984: University of Algiers 1 specializing in sciences, University of Algiers 2 for Arabic language and Islamic studies, and University of Algiers 3 for engineering. The National Library of Algeria, housed in a modernist building completed in 1994 in El Hamma district, contains approximately 1.5 million volumes including 40,000 manuscripts in Arabic, Ottoman Turkish, and Berber languages dating from the 9th century CE.
Algiers experiences a Mediterranean climate classified as Csa under Köppen categorization, with average annual temperatures of 18.5 degrees Celsius. January temperatures average 11.8 degrees Celsius, while August averages 25.5 degrees Celsius. Annual precipitation totals approximately 712 millimeters, concentrated between October and April, with July receiving an average of 5 millimeters. Humidity remains relatively consistent at 60 to 70 percent year-round due to coastal location. Winter temperatures rarely fall below 5 degrees Celsius at sea level, while summer temperatures occasionally exceed 38 degrees Celsius during sirocco conditions when hot air flows north from the Sahara.
The Port of Algiers handles approximately 5.5 million metric tons of cargo annually, serving as the nation's primary import facility for containerized goods and vehicles. The port infrastructure includes 27 berths totaling 5,400 meters of quay length, with depths ranging from 6 to 14 meters depending on basin. Container capacity reached 700,000 twenty-foot equivalent units (TEUs) in 2023. The port operates 24 hours daily with pilotage compulsory for all vessels exceeding 300 gross tons. A 3.3-kilometer breakwater protects the harbor from Mediterranean swells, constructed between 1899 and 1934 using concrete caissons filled with rock.