of the well-preserved wall paintings that adorned many of the churches. International interest in Cappadocia was awakened when he published his research in 1925, but the great underground cities were not discovered until the 1960s. Two of the largest so far unearthed are Derinkuyu, located in 1963, and Kaymakli, 6 miles (10 kilometers) to the south, a year later. They were once joined by a well-ventilated tunnel, almost certainly wide enough to allow three people to walk abreast.

Derinkuyu, probably dating from the eighth century and capable of housing a population of between 10,000 and 20,000 inhabitants, was built around a 280-foot-deep (84-meter) main air shaft. The ventilation system had at least fifty smaller vertical vents linked by narrow horizontal corridors. This network formed a multistory building “frame,” so to speak, and rooms—very comfortable living spaces, community kitchens, meeting rooms, chapels, stores, and even cemeteries—were cut to open from it. To date, eight levels have been excavated to a depth of 165 feet (55 meters), with twelve or more still buried. The top three levels appear to have been used as private and communal living quarters. Some scholars believe that each family unit had its own living room, bedroom, kitchen, toilet, and assorted storerooms. The lower levels housed storerooms and churches, and the lowest was a last resort of retreat in times of danger. It is possible that Derinkuyu was not permanently inhabited but served as a refuge at such times. Security was thus the main determinant in its planning: entrances were small and defensible, the ventilation outlets were carefully hidden, and there were several wells and a large cistern at the lowest level. Each section of the city could be isolated by large stone gates. Kaymakli was much the same, but only four of the eight levels remain accessible. The cities were last occupied during an Egyptian invasion in 1839.

Because of its unique geomorphic and cultural features, the entire region was added to UNESCO’s World Heritage List in 1985. At the beginning of the twenty-first century, the underground cities, constructed as they are of soft tufa, are under threat from two main sources. Increasing tourism is exposing them to accidental and, sadly, deliberate damage. More significant, climatic changes are turning the once-fertile surrounding agricultural land to desert. As farmers leave, the ecology changes: rainwater, once absorbed by vegetation, now permeates the soil, damaging the subterranean structures. Although appropriate technology is available to at least reduce deterioration, the severity of the problem and the fragility of the stone limit its application to the fascinating underground cities of Cappadocia.

Further reading

Demir, Ömer. 1990. Cappadocia: Cradle of History: Göreme. Ankara: International Society for the Investigation of Ancient Civilizations.

Kostof, Spiro. 1989. Caves of God: Cappadocia and Its Churches. New York: Oxford University Press.

Central Artery/Tunnel

Boston, Massachusetts

Toward the end of the twentieth century, Boston had traffic problems as severe as any city in the world. When the elevated six-lane Central Artery Highway, which ran through the downtown area, was opened in 1959, it quite easily coped with 75,000 vehicles a day; by the early 1990s the traffic load had increased to 190,000—effectively more cars per lane than any other urban interstate road in the United States. Movement was slowed to a snail’s pace for over ten hours each day, and the accident rate was four times the national average for similar thoroughfares. Moreover, the urban area was divided by the elevated road so that access between the north and south sectors was greatly restricted. Naturally, the same congestion characterized the two tunnels under Boston Harbor that joined downtown Boston with East Boston and Logan Airport; the airport, only 1 mile (1.6 kilometers) from the central business district, was an hour away by road!

The $10.8 billion Central Artery/Tunnel Project (CA/T), conceived in 1981 and under construction as of 2001 by the Massachusetts Turnpike Authority, deserves a place among the engineering marvels of the modern world. Referred to by Bostonians as the “Big Dig,” it is the largest, most complex highway project ever initiated in a U.S. city—indeed, the largest public works project of any kind in the United