Test 2 — The Lost City of Petra

Hidden among the sandstone canyons of southern Jordan lies Petra, once the capital of the Nabataean kingdom and one of the most remarkable cities of the ancient world. At its height, around the first century CE, Petra was home to perhaps thirty thousand people and stood at the crossroads of the caravan routes that carried incense, spices and silk from Arabia, India and China to the markets of the Mediterranean.

The Nabataeans were originally a nomadic Arab tribe. What set them apart was their genius for water management. Petra receives less than 150 millimetres of rain a year, yet the city supported gardens, fountains and even a small lake. Engineers cut channels, terracotta pipes and underground cisterns directly into the rock, capturing flash floods that would otherwise have been wasted. Some estimates suggest the network could store twelve million gallons of water — enough to survive the longest droughts.

The city's monumental façades, carved straight into pink-red cliffs, were largely tombs rather than dwellings. The most famous, known today as the Treasury (Al-Khazneh), is in fact a royal mausoleum almost forty metres high. Its Hellenistic columns and pediment betray the influence of distant Alexandria, while the carving technique — working from the top down to avoid scaffolding — was a Nabataean speciality.

Petra's wealth depended on its position. Caravans paid tolls to cross Nabataean territory, and the city's merchants supplied them with water, lodging and protection. When the Roman emperor Trajan annexed the kingdom in 106 CE, this commercial advantage began to erode. New sea routes through the Red Sea allowed traders to bypass overland caravans altogether, and a series of earthquakes — the most destructive in 363 CE — damaged the water system beyond easy repair.

By the time the Byzantine bishops left Petra in the seventh century, the city was largely empty. Local Bedouin continued to live among the ruins, but for medieval Europeans Petra disappeared entirely. It was not until 1812 that the Swiss explorer Johann Ludwig Burckhardt, disguised as a Muslim pilgrim, persuaded a guide to take him through the Siq, the narrow gorge that forms the city's natural entrance. His brief description electrified European scholars.

Today, around a million tourists visit Petra each year, and conservation has become an urgent concern. The same wind and water that originally shaped the rock now eat into the carvings at a measurable rate; salt crystallising in the porous stone causes "sugaring", in which entire surfaces crumble to dust. UNESCO and the Jordanian government are experimenting with breathable consolidants and with diverting visitor traffic away from the most fragile monuments.

Robotic surgery has progressed quickly from novelty to routine. The most widely used system, the da Vinci Surgical System, was approved by the United States Food and Drug Administration in 2000; by 2023, hospitals worldwide were performing over two million procedures with similar machines each year. The robot does not act on its own — every movement is directed by a surgeon seated at a nearby console — but the mechanical arms can pivot in ways no human wrist can match, and the magnified 3D view rivals that of a microscope.

Enthusiasts argue that the benefits are clear. In prostate cancer surgery, where the surgeon must work in a narrow space crowded with nerves, robotic assistance has been associated with lower rates of impotence and incontinence. In gynaecology, smaller incisions mean shorter hospital stays — typically one night instead of three or four. For patients, the visible scars are often little larger than a fingertip.

Yet sceptics warn that the evidence is less clear-cut than the marketing suggests. A 2018 study in The Lancet compared robotic and conventional surgery for bladder cancer and found no significant difference in survival or recovery time, but a substantially higher cost — roughly £3,000 more per case in the United Kingdom. Critics argue that hospitals which have invested several million pounds in a system are under pressure to use it, even when the clinical advantage is marginal.

A related concern is the long learning curve. Mastery of a complex robotic procedure typically requires between fifty and a hundred cases. During this period, complications can be more frequent than with traditional methods, and some studies suggest that early adopters' patients have served as unintentional training subjects. Professional bodies in several countries are now considering whether minimum case numbers should be made compulsory before surgeons operate independently.

The next generation of systems promises greater autonomy. At Johns Hopkins University, an experimental robot has performed soft-tissue surgery on pigs without a human at the controls, planning its own stitches with the help of computer vision. Its inventors are careful to describe it as a "supervised" rather than autonomous system; nevertheless, the trajectory is clear. Within a decade, simple closure tasks — sewing wounds or anchoring meshes — may be delegated entirely to machines.

Whether such progress will translate into broader access is another question. Robotic systems remain expensive to buy and maintain, and most are concentrated in wealthy urban hospitals. Some researchers are working on simpler, single-arm devices intended for low-resource settings; one prototype, developed in India, costs less than one-tenth of a da Vinci. If that price point can be sustained, the geography of advanced surgery could change significantly.

Of the roughly seven thousand languages spoken on Earth today, linguists estimate that almost half are likely to fall silent before the end of this century. A language is generally considered safe only when children continue to learn it as their first tongue and use it across every domain of life. By that standard, only a few hundred languages are securely positioned for the long term; the rest are in varying states of vulnerability.

Languages die for many reasons, but rarely because their speakers are incapable of maintaining them. Far more often, the cause is a calculation — sometimes individual, sometimes imposed by the state — that a different language offers better prospects. In nineteenth-century France, schoolchildren in Brittany were beaten for speaking Breton; in Australia, generations of Aboriginal children were removed from families precisely so that they would lose their mother tongue. The effects of such policies persist long after the policies themselves are abandoned, because once a generation fails to learn a language, transmission cannot easily be restarted.

Economic pressure can operate without any deliberate prohibition. In rural Mexico, a child who speaks only Zapotec is unlikely to find work outside the village; one who masters Spanish has access to schooling, jobs and the wider media. Parents who decide to raise their children in Spanish are making a rational choice, even if they regret the consequence. Multiply that decision across thousands of families, and the language withers within a generation or two.

What is lost when a language disappears? Some argue that the answer is "nothing essential", because complex thought is possible in any language. Others reply that each language encodes a distinctive way of organising experience — a system of metaphors, kinship terms, ecological knowledge and verbal art that cannot be fully translated. The Inuit dialects of northern Canada, for instance, contain dozens of finely graded terms for sea ice and snow that have no equivalents in English; these are not poetic curiosities but practical knowledge built up over centuries of observation.

Revival is possible but extraordinarily difficult. Hebrew offers the most spectacular success: a liturgical language with no native speakers in the nineteenth century, it now has nine million. Yet the conditions of that revival — a strong national movement, a defined territory, mass immigration of multilingual settlers — are seldom available elsewhere. More modest gains have been recorded for Welsh, Māori and Hawaiian, all of which combine school instruction with broadcasting and digital media. The lesson of these cases is that policy works only when communities themselves want to speak.

Linguists today increasingly see their role as collaborative rather than purely descriptive. Documentation projects record fluent elders on video, train younger community members in linguistic analysis, and produce dictionaries and teaching materials that the community itself can use. Whether such efforts ultimately reverse language loss or merely slow it remains uncertain. Either way, the next century will see the linguistic landscape of humanity reshaped on a scale unmatched since the spread of agriculture.