Dammam

On 4 March 1938, Dammam Well No. 7 struck oil at 1,440 metres depth. The well would produce more than 32 million barrels before its closure in 1982, but its real output was a city. What had been a fishing hamlet of a few thousand people became the capital of a metropolitan area now approaching three million — a roughly 130-fold increase since 1950. Dammam did not grow into a city; it was manufactured into one.

Giant tube worms cluster around deep-sea hydrothermal vents, growing up to three metres in length at rates that make them among the fastest-growing marine invertebrates on Earth. They have no mouth and no digestive system. Instead, they harbour chemosynthetic bacteria that convert hydrogen sulphide from the vent into organic compounds — an internal power plant fuelled entirely by subterranean energy. When the vent goes cold, the colony dies.

Dammam runs on the same architecture. The city has no rivers and no lakes. Its limestone aquifers, while they exist, are being depleted far faster than they recharge, and the majority of the metropolitan area's drinking water comes from energy-intensive desalination plants funded by hydrocarbon revenues. Oil pays for the desalination that produces the water that sustains the workers who extract the oil — a closed metabolic loop where the extractive resource subsidises the basic conditions of human habitation.

The triplet cities of Dammam, Dhahran, and Khobar function as specialised organs of a single organism. Dammam houses King Abdulaziz Port — the largest in the Arabian Gulf, with a handling capacity exceeding 100 million tonnes across 43 berths — and serves as the administrative centre. Dhahran hosts Saudi Aramco's global headquarters and King Fahd University of Petroleum and Minerals. Khobar provides the residential and commercial tissue. Each city performs a function the others cannot, a division of labour that mirrors the tube worm's internal partitioning between its trophosome, its gill-like plume, and its structural tube.

Saudi Arabia's Vision 2030 programme is, in biological terms, an attempt to evolve a digestive system before the vent goes cold — to diversify the Eastern Province's economy beyond the single subterranean energy source that called the city into being. Whether a tube worm can learn to eat remains the defining question.