Hell Is Other People's Misconceptions

New Delhi from space, photographed by the ESA's Copernicus Sentinel-2 satellites

Spend enough time on Reddit, and you inevitably learn odd things about other people. I've learned, for example, that if you put an unlabeled map of a fictional world (or even the real one) in front of a bunch of nerds and ask them where civilizations should develop and where large cities should appear, the vast majority of them will point to the mouths or deltas of that map's largest rivers. Which is wrong! And who can stand to see other people be wrong on the internet? Not I.

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You can get pretty far into the weeds trying to define “civilization” and pinpoint the places where it independently arose, but it's not much of an oversimplification to say that it happened, at least on our planet, in river valleys. In valleys along the Mexican Gulf Coast, the Olmec civilization emerged; in valleys along the Peruvian Pacific Coast, the Caral–Supe civilization. (These were actually pretty close to the sea, with cities like La Venta and Caral being within a day's walking distance of the shore, but still: river valleys.) The Egyptian civilization, famously, emerged in the Nile valley, far upstream of the river's enormous delta. Where exactly civilization first appeared in the Fertile Crescent is kind of an open question, but all of the likely sites are, you guessed it, river valleys, and of course the famous city-states that went on to invent writing, math, the wheel, and boots appeared along the banks of the Tigris and Euphrates. Likewise, the exact spot where civilization first appeared in China, insofar as you can identity such a thing exactly (you can't), is disputed, but basically: the Yellow, Yangtze, and Liao valleys. And the Indus Valley Civilization? It's right there in the name.

So, okay, they form upstream, but then they move down to the shore, right? Well, yes and no. Mostly no, at least until modern times. River mouths were generally unsuitable for ancient cities both because of a lack of fresh water (estuarine water is brackish) and because river sedimentation caused floods and led the watercourse to shift regularly, which could drown a settlement or leave it stranded inland. Dredging, canal-building, and aqueducts (among other technologies) made it feasible to put large cities near river mouths, but even then, a city like Alexandria is actually well to the west of the river. (And of course Alexandria was a classical-era Greek city, not an ancient Egyptian one; every major ancient Egyptian city was built above the Nile delta, and even Canopus and Heracleion, the much smaller predecessors of Alexandria, were just west of the delta.)

Many major ancient port cities, like Carthage and Constantinople, weren't built anywhere near major rivers, but rather on peninsulas that controlled sea lanes; they depended on huge rainwater cisterns and aqueducts to sustain them. Few major Mesoamerican cities were built on the coast, and fewer still along large rivers. The one urban civilization in North America that built along a major river, the Mississippians, did so 1,000 kilometers from the ocean.

Even today, most of the world's largest cities are not coastal. Delhi, São Paulo, Mexico City, Chengdu, Cairo, Beijing, Dhaka, Tehran, Kolkata, Guangzhou, Moscow, Paris, Seoul, London, Kuala Lumpur, Johannesburg, Kinshasa, Wuhan, Riyadh: all inland. Most of the major coastal cities today have colonial-era foundations (Karachi, New York, Rio de Janeiro, Buenos Aires, Chennai, Mumbai, Lagos, Manila, etc.) or are otherwise recent developments (Tianjin, Shenzhen, Saint Petersburg, Dubai, etc.).

There are some interesting exceptions (most big Japanese cities, and particularly Osaka, which has been a major port for almost 2,000 years; Jakarta; Shanghai and Hangzhou; and of course Istanbul), but they are unusual. Even with centuries of colonialism and globalized trade having driven the development of huge ports on every populated seaboard, and in spite of a colossal population boom in the last hundred years, the vast majority of the world's population still lives inland; fewer than 30% of us live within 50 kilometers of the coast.