The World Without Us - Alan Weisman (2007)

Part II

Chapter 8. What Lasts

1. Earth and Sky Tremors

I

T IS HARD to see exactly what holds up the enormous round dome of Istanbul’s formerly Orthodox Christian, marble and mosaic-encrusted church of Hagia Sophia. More than 100 feet across, it is slightly smaller than the dome that crowns Rome’s Pantheon, but considerably higher. An inspired stroke of design divides its weight through a colonnade of arched windows at its base, making it appear to float. To gaze straight up at it, a gilded sky hovering 185 feet overhead, with no easy sense of why it stays aloft, leaves a beholder half-believing in miracles, and half-dizzy.

Over a thousand years, the dome’s weight has been further distributed among so many redoubled interior walls, additional half-domes, flying buttresses, pendentives, and massive corner piers that Turkish civil engineer Mete Sözen believes that not even a major earthquake would easily shake it loose. That is exactly what happened to its first dome, which fell just 20 years after it was completed in AD 537. That mishap led to all the subsequent reinforcement; even so, quakes severely damaged the church (which became a mosque in 1453) twice more until Mimar Sinan, the greatest architect of the Ottoman Empire, restored it in the 16th century. The delicate minarets the Ottomans added to its exterior will one day topple, but even in a world without people, meaning no masons to periodically repoint the Hagia Sophia’s mortar, Sözen expects much of it and other great ancient masonry edifices of Istanbul to last well into future geologic time.

Which is more than he can say, unfortunately, for the rest of the city of his birth. Not that it’s quite the same city. Through history, Istanbul, née Constantinople, née Byzantium before that, has changed hands so many times that it’s hard to imagine what could fundamentally alter it, let alone destroy it. But Mete Sözen is convinced that the former has already happened and the latter is imminent, whether humans stick around or not. The only difference in a world without people is that no one would be left to try to pick up Istanbul’s pieces.

When Dr. Sözen, who holds a chair in structural engineering at Indiana’s Purdue University, first left Turkey in 1952 for graduate studies in the United States, Istanbul had 1 million people. Half a century later, it has 15 million. He describes that as a far greater paradigm shift than its previous transformations from Delphic to Roman to Byzantine Orthodox to Crusader Catholic and, finally, to Muslim—in all its Ottoman and Turkish Republican strains.

Dr. Sözen sees this difference through an engineer’s eyes. Whereas all the previous conquering cultures erected fabulous monuments to themselves like the Hagia Sophia and the nearby ethereal Blue Mosque, the architectural expression of today’s hordes is manifest in more than 1 million multi-story buildings jammed into Istanbul’s narrow streets—buildings that he says are doomed to abbreviated life spans. In 2005, Sözen and a team he assembled of international architectural and seismic experts warned the Turkish government that within 30 years, the North Anatolian Fault that runs just east of the city will slip again. When it does, at least 50,000 apartment buildings will fall.

He’s still awaiting a response, although he doubts that anyone can imagine where to begin to stave off what his expertise deems inevitable. In September 1985, the U.S. government rushed Sözen to Mexico City to analyze how its embassy had weathered an 8.1-magnitude earthquake that collapsed nearly 1,000 buildings. The highly reinforced embassy, which he had examined a year earlier, was intact. Up and down Avenida Reforma and adjacent streets, however, many high-rise offices, apartments, and hotels had disintegrated.

It was one of the worst quakes in Latin American history. “But it was mostly confined to downtown. What occurred in Mexico City is a flake of what will happen to Istanbul.”

One thing that the two disasters, past and future, have in common is that nearly all the buildings that crumbled or will crumble were built after World War II. Turkey stayed out of that war, but its economy took the same beating as every other country’s. As industries recovered in the postwar European boom, thousands of peasants migrated to cities everywhere seeking jobs. Both the European and Asian sides of the Bosphorus Strait, which Istanbul straddles, filled with six- and seven-story housing of reinforced concrete.

“But the quality of the concrete,” Mete Sözen told the Turkish government, “is 1/10 of what you’d find in, say, Chicago. Strength and quality of concrete depend on the amount of cement used.”

Back then, the problem was economics and availability. But as Istanbul’s population grew, the problem did, too, with more floors added to accommodate more humans. “The success of a concrete or masonry building,” Sözen explained, “depends on how much you have to support above the first level. The more floors, the heavier the building.” The danger comes when residential stories are stacked on top of structures whose ground floors are used for shops or restaurants. Most are open commercial spaces that lack internal columns or load-bearing walls because they were never intended to support more than one story.

Complicating matters further, floors added as afterthoughts rarely align in adjacent buildings, placing uneven stress on shared walls. Worse still, Sözen said, is when space is left at the top of a wall for ventilation, or to save material. When a building sways during an earthquake, exposed columns in partial walls shear off. In Turkey, hundreds of schools have just such a design. Wherever air-conditioning is unaffordable in the tropics, from the Caribbean to Latin America to India to Indonesia, these extra spaces are especially common as a way to bleed off heat and invite breezes. In the developed world, the identical weakness is often found in structures without climate control, such as parking garages.

In a 21st century where more than half the human race lives in cities and where most people are poor, cheap variations on the theme of reinforced concrete are repeated daily: planet-wide piles of low bids that will come crashing down in a posthuman world, and do so even faster if the city is near a fault line. When an earthquake strikes Istanbul, its narrow, winding streets will clog so totally with the rubble of thousands of wrecked buildings, Sözen estimates, that much of the city will simply have to close down for 30 years before the massive destruction can be cleared away.

Assuming there is anybody to do the clearing. If not, and if Istanbul remains a city where snow regularly falls in the winter, then freeze-thaw cycles will have plenty of earthquake detritus to reduce to sand and soil above the cobbles and pavement. Every earthquake causes fires; in the absence of response crews, the grand old wooden Ottoman mansions along the Bosphorus will contribute the ash of long-extinct cedars to the formation of new soil.

Although mosque domes, like the Hagia Sophia’s, will initially survive, the shaking will have loosened their masonry, and freeze-thaw will work at their mortar until bricks and stones start to fall. Eventually, as in 4,000-year-old Troy 175 miles down Turkey’s Aegean coast, only Istanbul’s roofless temple walls will remain—still standing, but buried.

2. Terra Firma

Should Istanbul exist long enough to complete its planned subway system—including a line under the Bosphorus that would link Europe and Asia—since its tracks will cross no fault line, it will probably remain intact, albeit forgotten, long after the city on the surface is gone. (Subways whose tunnels do encounter geologic faults, however, such as the San Francisco Bay Area’s BART and New York City’s MTA, may face another fate.) In the Turkish capital of Ankara, the subway system’s central nerve core broadens into an extensive underground shopping district with mosaic walls, acoustic ceilings, electronic billboard screens, and arcades of stores—an orderly underworld compared to the cacophony of the streets above.

Ankara’s sub-surface shops; Moscow’s subway, with its deep train tunnels and chandelier-lit, museum-like underground stations, renowned as some of the most elegant spots in the city; Montreal’s subterranean village of shops, malls, offices, apartments, and labyrinthine passages that reflect the city in miniature and link its old-fashioned surface structures—all these underground creations stand the best chance of any man-made edifices of lasting into whatever hereafter lies beyond human existence on Earth. Although seepage and surface cave-ins will eventually reach them, buildings still exposed to the elements will go well before structures that were born already buried.

These won’t be the oldest, however. Three hours south of Ankara is a region of central Turkey whose name, Cappadocia, ostensibly means “Land of Fine Horses.” But that has to be a mistake: the result, possibly, of some garbled pronunciation of a more fitting description in some ancient tongue, because not even winged horses could steal the spotlight from this landscape—or from what lies beneath it.

In 1963, a fresco now thought to be the oldest landscape painting on Earth was discovered in Turkey by University of London archaeologist James Mellaart. Between 8,000 and 9,000 years old, it is also the oldest known work rendered on a surface constructed by humans: in this case, a mud-brick plastered wall. Overtly two-dimensional, the eight-foot mural is a flattened image of an erupting, double-coned volcano. Out of context, its components make little sense: The volcano itself, painted with ochre pigments worked into wet lime plaster, could be mistaken for a bladder, or even two disembodied breasts—in this case, the teats of a female leopard, as they are curiously flecked with black spots. The volcano also seems to be perched directly atop a pile of boxes.

From the vantage point of where it was discovered, however, its meaning is unmistakable. The double-barreled volcano’s shape matches the silhouette of 10,700-foot Hasan Da 40 miles to the east, a long swoop of a mountain that hangs over central Turkey’s high Konya plain. Together, the boxes form a primitive town plat of what many scholars consider the world’s first city, Çatal Höyük, which is twice as old as the pyramids of Egypt—and, with a population around 10,000, was far bigger than its contemporary, Jericho.

All that remained of it when Mellaart began digging was a low mound rising above wheat and barley fields. The first things he found were hundreds of obsidian points, which may explain the black spots, as the Hasan Da volcano was the source for that substance. But for reasons unknown, Çatal Höyük had been abandoned. The mud-brick walls of its house-sized boxes had fallen in on themselves, and erosion smoothed the rectangles of its skyline into a gentle parabola. Another 9,000 years, and the parabola should be long flattened.

On Hasan Da’s opposite slope, however, something quite different happened. What is now called Cappadocia began as a lake. During millions of years of frequent volcanic eruptions, its bowl filled with layers of ash that kept piling on, hundreds of feet deep. When the cauldron finally cooled, these congealed into tuff, a rock with remarkable properties.

A huge, final burst 2 million years ago unrolled a mantle of lava that left a thin crust of basalt atop 10,000 square miles of powdery gray tuff. When it hardened, so did the climate. Rain, wind, and snow set to work, with freeze-thaw cycles cracking and splitting the basalt pavement, and moisture seeping in to dissolve the tuff below. As it eroded, in places the ground collapsed. Left standing were hundreds of pale, slender pinnacles, each mushroom-capped with a hood of darker basalt.

Tourism promoters call them fairy towers, a plausible descriptor but not necessarily the first one that comes to mind. The magical version prevails, however, because the surrounding tuff hills have invited not just wind and water to sculpt them, but also the hands of imaginative humans. Cappadocia’s towns have not been built so much on the land, as in it.

Tuff is soft enough that a determined prisoner here could scoop his way out of a dungeon with a spoon. When exposed to air, however, it hardens, forming a smooth, stucco-like shell. By 700 BC, humans with iron tools were burrowing into Cappadocia’s escarpments, and even hollowing out fairy towers. Like a prairie dog village tipped on its side, every rock face was soon riddled with holes—some big enough for a pigeon, or a person, or a three-floor hotel.

The pigeonholes—hundreds of thousands of arched niches hollowed into valley walls and pinnacles—were intended to attract rock doves for exactly the same reason humans in modern cities try to chase their urban cousins away: their copious droppings. So prized was pigeon guano, used here to nourish grapes, potatoes, and famously sweet apricots, that the carved exteriors of many dovecotes bear flourishes as ornate as those found on Cappadocia’s cave churches. This architectural homage to a feathered fellow creature continued until artificial fertilizers reached here in the 1950s. Since then, Cappadocians no longer build them. (Nor do they now build churches. Before the Ottomans converted Turkey to Islam, more than 700 were cut into Cappadocia’s plateaus and mountainsides.)

Much of today’s most expensive real estate here consists of luxury homes carved into tuff, with bas-relief exteriors as pretentious as the facades of mansions anywhere, and with mountainside views to match. Former churches have been recast into mosques; the muezzin call to evening devotion, resounding among Cappadocia’s slick tuff walls and spires, is like a congregation of mountains praying.

One distant day, these man-made caves—and even natural ones, of stone much harder than volcanic tuff—will wear away. In Cappadocia, however, the stamp of humanity’s passage will linger beyond our other traces, because here humans have not only ensconced themselves in plateau walls, but also beneath the plains. Deep beneath. Should the Earth’s poles shift and sheet glaciers one day muscle their way across central Turkey, flattening whatever man-made structures still stand in their way, here they will only scratch our surface.

No one knows how many underground cities lie beneath Cappadocia. Eight have been discovered, and many smaller villages, but there are doubtless more. The biggest, Derinkuyu, wasn’t discovered until 1965, when a resident cleaning a back room of his cave house broke through a wall and discovered behind it a room that he’d never seen, which led to still another, and another. Eventually, spelunking archaeologists found a maze of connecting chambers that descended at least 18 stories and 280 feet beneath the surface, ample enough to hold 30,000 people—and much remains to be excavated. One tunnel, wide enough for three people walking abreast, connects to another underground town six miles away. Other passages suggest that at one time all of Cappadocia, above and below the ground, was linked by a hidden network. Many still use the tunnels of this ancient subway as cellar storerooms.

Unlike a river canyon, the earliest segments here are nearest the surface. Some believe the first builders were the Hittites of biblical times, who burrowed underground to hide from marauding Phrygians. Murat Erturul Gülyaz, an archaeologist at Cappadocia’s Nevehir Museum, agrees that Hittites lived here, but doubts they were the first.

Gülyaz, a proud native with a moustache thick as a fine Turkish rug, worked on the excavation of Aikli Höyük, a small Cappadocian mound containing the remains of a settlement even older than Çatal Höyük. Among the relics there were 10,000-year-old stone axes and obsidian tools capable of cutting tuff. “The underground cities are prehistoric,” he declares. That, he says, explains the crudeness of the upper chambers, compared to the precision of the rectangular floors below. “Later, every-one who appeared kept going deeper.”

Underground city, Derinkuyu, Cappadocia, Turkey.

PHOTO BY MURAT ERTUGRUL GÜLYAZ.

It’s as if they couldn’t stop, one conquering culture after another realizing the benefit of a hidden, sub-surface world. The underground cities were lit by torches, or often, Gülyaz discovered, by linseed oil lamps, which also gave enough heat to keep temperatures pleasant. Temperature was probably what first inspired humans to dig them, for winter shelter. But as successive waves of Hittites, Assyrians, Romans, Persians, Byzantines, Seljuk Turks, and Christians discovered these dens and warrens, they widened and deepened them for one principal reason: defense. The last two even expanded the original upper chambers enough to stable their horses underground.

The smell of tuff that permeates Cappadocia—cool, clayish, with a menthol tang—intensifies below. Its versatile nature allowed niches to be scooped where lamplight was needed, yet tuff is strong enough that Turkey considered using these nether cities as bomb shelters had the 1990 Persian Gulf War spread.

In the underground city of Derinkuyu, the floor below the stables held fodder bins for livestock. Next down was a communal kitchen, with earthen ovens placed below holes in nine-foot ceilings that, via offset rock tubes, channeled smoke to chimneys two kilometers away, so that enemies wouldn’t know where they were. For the same reason, ventilation shafts were also engineered on the skew.

Copious storage space and thousands of earthenware jars and urns suggest that thousands of people spent months down here without seeing the sun. Through vertical communication shafts, it was possible to speak to another person on any level. Underground wells provided their water; underground drains prevented flooding. Some water was routed through tuff conduits to underground wineries and breweries, equipped with tuff fermentation vats and basalt grinding wheels.

These beverages were probably essential for calming the claustrophobia induced by passing between levels via staircases so intentionally low, tight, and serpentine that any invaders had to proceed slowly, bent over, and in single file. Emerging one by one, they would be easily slain—if they got that far. Stairways and ramps had landings every 10 meters, with Stone Age pocket doors—half-ton, floor-to-ceiling stone wheels—that could be rolled in place to seal a passage. Trapped between a pair of these, intruders would soon notice that holes overhead weren’t air shafts, but pipes for bathing them with hot oil.

Another three floors below this underworld fortress, a room with a vaulted ceiling and benches facing a stone lectern was a school. Farther below were multiple levels of living quarters, strung along underground streets that branched and intersected for several square kilometers. They included double alcoves for adults with children, and even playrooms featuring pitch-black tunnels that returned to the same spot.

And farther: eight levels down in Derinkuyu, two large, high-ceilinged spaces join in a cruciform. Although, due to constant humidity, no frescoes or paintings remain, in this church, seventh-century Christians who emigrated from Antioch and Palestine would have prayed and hidden from Arab invaders.

Below it is a tiny, cube-shaped room. It was a temporary tomb, where the dead could be kept until danger passed. As Derinkuyu and the other underground cities passed from hand to hand and civilization to civilization, their citizens always returned to the surface, to bury their own in the soil where food grew under sun and rainfall.

The surface was where they were bred to live and die, but one day when we are long gone, it is the underground cities they built for protection that will defend humanity’s memory, bearing final—albeit hidden— witness to the fact that, once, we were here.