Cairo

Cairo produces 22% of Egypt's GDP with 11% of its population — a metabolic concentration that would kill most organisms. The city proper holds roughly 10 million people, but Greater Cairo sprawls across 23 million, making it Africa's largest metropolitan area and the Arab world's most populous city. The official narrative centres on the Pyramids, the Nile, and pharaonic heritage. What it underplays is that Cairo is one of the most extreme examples of informal urbanisation on earth.

The city was founded in 969 AD by the Fatimid dynasty as a royal enclosure north of the older settlement of Fustat, itself built by Arab conquerors in 641 AD atop Roman-era Babylon fortress. Cairo's location was not accidental: the Nile narrows here before splitting into the Delta, creating a natural chokepoint where trade, governance, and military power converge. Every ruler from the Mamluks to the British understood that controlling this spot meant controlling the flow between Upper Egypt's agriculture and the Mediterranean trade routes.

The modern city's defining feature is its informal housing. Over 63% of Greater Cairo's residents live in neighbourhoods built without official planning — not slums in the conventional sense, but self-organised construction that houses millions in structures of varying quality. These informal areas occupy just 17% of the city's land but contain the majority of its people. This is not failure; it is emergent order. The informal housing sector functions like a biological system responding to resource pressure: when formal channels cannot allocate shelter fast enough for a population growing at 2% annually, self-organisation fills the gap. Cairo's informal economy — estimated at 30-40% of national GDP — follows the same pattern.

Egypt's construction sector alone is valued at $55 billion and contributes 14% of GDP, much of it concentrated in Greater Cairo's ongoing expansion. The New Administrative Capital, under construction 45km east of the old city, represents the government's attempt to relieve pressure — but it also reveals the core problem. Cairo has grown beyond the carrying capacity of its infrastructure, yet it cannot stop growing because it remains the only real economic attractor in a country of 118 million. Tourism contributes 13.8% growth, non-oil manufacturing expanded 14.5% in early fiscal year 2025/26, and the city was ranked Africa's top business destination.

This is positive feedback in its purest form: economic opportunity draws migration, migration increases density, density increases economic activity, which draws more migration. The biological parallel is a colony organism — like a termite mound — where individual units self-organise into a functional superstructure without central planning, continuously expanding until resource limits impose a correction.