The cheese worth breaking bones for, the island the Dutch chose over Manhattan, and concrete that mends itself

Cooper's Hill drops about two hundred yards over ground that pitches to roughly one in two, close to sheer at its steepest.[1] No one comes down it with any dignity. Competitors lose their footing within a stride and finish the descent as a tumble of arms and legs, which is why volunteers wait at the bottom to catch them before they reach the road.[1][2]

Injuries come with the hill. Sprains, dislocations and the occasional broken bone are routine, first-aiders and an ambulance stand by, and in one rough year fifteen people were hurt, four of them seriously.[1] The winner of the women's race in 2023 crossed the line unconscious and came round in the medical tent, unaware she had won.[4]

How the custom began is not really known. The first written record is a message read out to the Gloucester town crier in 1826, and by then the race was already spoken of as an old tradition.[1][2] The usual explanations point two ways, one practical and one older and stranger: that villagers rolled the cheese to assert a common right to graze the hill, or that the event descends from a spring rite in which burning brushwood was sent down the slope to mark the turning year.[2] The folklorist Steve Roud treats it as the last surviving fragment of the old Cooper's Hill Wake, the parish feast the race is still named for.[2]

The prize is real, an eight-pound wheel of Double Gloucester supplied since 1988 by the Smart family of local cheesemakers.[1] Once, in 2013, a foam replica stood in for it on safety grounds, and the real thing returned the next year.[1] The event lost its official organisers around 2010, after the crowds grew unmanageable, yet it has run every spring without them, staged by volunteers and called off only for the pandemic.[1][2] It also keeps minting champions. Chris Anderson, a former soldier from Brockworth, holds the world record with twenty-three wins between 2005 and 2022, and the race now pulls competitors from well beyond Gloucestershire, including a German video-maker who took the men's title two years running.[3][5][6]

For all the ambulances, the appeal is easy to see. The race asks nothing of a competitor but nerve, it rewards the winner with a wheel of cheese and a few days of fame, and it has outlasted every attempt to make it safe or to shut it down.[2][5]

For a century and more, nutmeg was among the most valuable substances in Europe, and almost all of it came from one small cluster of islands. The tree that bears it, which botanists call Myristica fragrans, grew nowhere the wider world could reach except the Banda Islands, a handful of volcanic dots in what is now eastern Indonesia.[1][2] The same fruit yields two spices at once, the seed sold as nutmeg and the scarlet web around it sold as mace.[1] Europeans prized both as flavour and as medicine, and believed, wrongly, that nutmeg could keep the plague at bay, which lent it the pull of a cure.[3]

The markups were the stuff of legend. Nutmeg bought on Banda for a fraction of a penny could sell in London or Amsterdam for more than two pounds, a rise later writers put at over sixty thousand per cent, and prices like that were worth killing for.[3] To hold the monopoly, the Dutch East India Company set out to control Banda outright. In 1621 an expedition under Jan Pieterszoon Coen took the islands by force and destroyed the people who lived there; of a population of roughly fifteen thousand, only about a thousand were left afterwards, the rest killed, enslaved or driven out.[4] The Company then replanted the groves and worked them with enslaved labour.[4]

One island held out. Run lay at the far western edge of the group, and its people had sworn allegiance to the English crown, which made the little island one of England's earliest overseas claims.[5] An East India Company agent named Nathaniel Courthope held it against the Dutch for more than four years, a defence of some fifteen hundred days that ended only when he was killed in 1620.[5] The English later left the island, but they never quite surrendered the claim.

That unresolved claim was still on the table in 1667, when the Treaty of Breda ended the second of the naval wars between the two powers.[6] The settlement ran on a plain principle, that each side simply kept whatever it already held.[6][7] The Dutch held Run and kept it; the English held New Amsterdam, seized three years earlier and already renamed New York, and kept that.[6] No one at the table bartered one island for the other in so many words, and the tidy story of a swap is a later invention, but the outcome was plain enough. The Dutch secured the nutmeg and let the future Manhattan go.[7]

The monopoly they had killed for did not last. In the seventeen-seventies a French official smuggled spice seedlings out of the islands, and during the Napoleonic wars the British seized Banda and carried nutmeg off to plant in their own tropical colonies, from Ceylon to Penang.[2][8] Later the tree reached Grenada, in the Caribbean, which took to it so completely that it set a nutmeg on its national flag.[9] The spice that once bought an island is now a jar on a shelf, and Run, the speck given up for a continent's greatest city, is a quiet place where a few hundred people still grow it.[2][5]

Roman builders made their concrete, which they called opus caementicium, from lime, lumps of rock, and a particular volcanic ash they mined near the Bay of Naples, at a town the Romans knew as Puteoli.[5] That ash, later named pozzolana after the place, reacts with lime and water to set into a hard binder, and Roman engineers valued it enough to ship it across the empire.[5] What set the best Roman mixes apart, though, was something their makers may not have fully understood themselves.

Scattered through the old concrete are small white lumps of lime, a few millimetres across, that scholars long read as a sign of careless mixing.[2] A team led by researchers at the Massachusetts Institute of Technology argued in 2023 that the lumps are nothing of the kind.[1] They form, the team proposed, because the Romans mixed their lime hot, using caustic quicklime straight from the kiln, the raw calcium oxide, rather than lime first slaked with water, and the method leaves reactive calcium locked inside those white clasts.[1][2]

Those clasts turn out to be a repair kit built into the wall. When a crack works its way through the concrete and rainwater seeps in, it meets the lime lumps, dissolves them, and the calcium recrystallises across the gap as fresh mineral, gluing the fissure shut before it can spread.[1][2] Where volcanic ash is present, the same calcium-rich water can react with it to grow new binder as well.[1] To test the idea, the team cast two batches of concrete, one made the Roman way and one lacking the reactive lime, cracked them both, and ran water through.[2] The Roman-style cracks sealed over and the flow stopped within a few weeks; the plain samples simply kept leaking.[2][3]

The sea gave the Romans a second trick, a quite different one. Studying concrete from harbour walls that have sat in salt water since antiquity, the geologist Marie Jackson has found that seawater slowly percolating through the material drives it to grow rare interlocking minerals over the centuries, so that the concrete does not merely resist the sea but is strengthened by it.[4] Modern cement is designed to keep water out and to hold its structure fixed; the Roman marine mix did the opposite, and gained from it.[4]

The hot-mixing account is a leading explanation and not the last word, and its authors present it as their proposal rather than settled fact.[1][2] The stakes in settling it are not only historical. Making modern cement pours a large share of the world's carbon into the air, on the order of eight per cent, so a concrete that mended its own cracks and lasted centuries instead of decades would be worth a great deal, and the Romans seem to have been making it two thousand years ago without knowing quite why it worked.[2]