COLUMN ONE : There’s No Stopping Istanbul : Muslim metropolis is in the grips of breakneck modernization, gaining renewed eminence for the old capital of Byzantine emperors and Ottoman sultans.

For almost all of this century, the floating Galata Bridge across the Golden Horn was a revered icon of a city that is a tail of two continents. One recent morning, tugboats towed the old iron bridge away.

So much for the thronged, colorful trademark of Istanbul as linchpin between West and East, Europe and Asia.

More pertinent now in a city busily consuming its past in the name of a Gargantuan but uncertain future is the replacement steel bridge. It is higher, wider and endlessly congested--an apt new symbol of a febrile, middle-of-the Earth Muslim metropolis on the make.

Sixteen centuries after the Emperor Constantine founded a new capital for the Roman Empire on the wooded banks of the Bosporus, Istanbul is undergoing a millennial change of face and personality, with important implications for the tough eastern Mediterranean neighborhood where it lives, and both continents that it spans.

Breakneck modernization combined with a flood of earnest and conservative immigrants from the Turkish countryside are recasting the face, customs and religious undertone of a traditionally liberal, sophisticated port.

“The Ottomans took the city in 1453, but the real Turkish conquest of Istanbul is now,” said Celik Gulersoy, head of the Turkish automobile club, which has managed to rescue some graceful old wooden buildings and a spectacular hillside park from rapacious development.

In downtown Istanbul, singles bars jostle 400-year-old mosques in streets that taste of pollution, poverty and pride. There is palatial splendor in an old imperial city whose air sometimes looks as bad as it often smells. And there is sweat-shop, 10-living-in-one-room squalor.

At heart, though, there may be no other place on Earth where Islam and diversity are such good neighbors. Anything goes. In one old village swallowed by Istanbul’s sprawl, yuppie fish restaurants and traditional lamb parlors coexist with a takeout Chinese restaurant run by Korean Christian fundamentalists. Istanbul’s prosperous Jewish community is celebrating its 500th anniversary.

Suddenly, Istanbul is Europe’s youngest big city--and is one of its most burgeoning metropolises.

“We are in a permanent state of explosion,” said Mayor Nurettin Sozen. “Istanbul is today Europe’s largest and fastest-developing metropolis. In my lifetime, its population has gone from 800,000 in the ‘40s to the present 10 million--more than three-quarters of the countries in Europe.”

Half a million new residents arrive each year--one a minute, 60% of them from rural Turkey. Sami Camoglu’s minute came in a cold, wet dawn one recent day at the Topkapi main bus station near a gate in the old Byzantine city wall. Stiff from an all-night ride from Ordu province on the Black Sea, the 27-year-old worker tumbled from the bus with two plastic weave fertilizer bags and a familiar story.

“There’s no work at all at home. It’s cold, snow everywhere,” he said. “Here, there’s work on building sites. I want to settle, maybe get a wife. I hope it will be better here.”

Like Turkey, the metropolis on the Bosporus has feet, and heart, in two continents. And dreams enough for all seven. Istanbul is reaching out to the world, demanding to be recognized. It is pushing hard to be host of the 2000 Summer Olympics. As it grapples with the daunting, sometimes depressing challenges of exponential growth, Istanbul is a city to be reckoned with as pivot of a brawny, singular nation that is the world’s only secular Muslim democracy.

Istanbul is the national center for Turkey’s industry, commerce and shipping. Half of everything made in Turkey is made in Istanbul. It manufactures everything from blue jeans to razor blades to gold bracelets. It still retains its reputation as an entrepot for illegal drugs. Its port, its trade, its bustle dwarf regional competitors--from Athens to Odessa.

In the past year alone, Istanbul has welcomed a new private television channel every month--and a hotel-casino that has become home to one of the world’s highest stake games of five-card stud poker.

The ‘tween-continents giant is growing even faster than the nation, whose gross national product increased 5.5% and whose exports grew 10% in 1992, despite a global recession. Istanbul’s 10 million people generate half the taxes for a nation of 60 million.

Renewed eminence for the old capital of Byzantine emperors and Ottoman sultans is rewriting regional rules for trade, commerce, industry and the movement of people. The new Istanbul’s appeal draws a rapt paying audience: banks, airlines, multinational corporations, diplomats, tourists.

Istanbul is a regional rarity: a huge, free-market magnet with strong growth, available capital and labor and a relatively stable democratic government. Half of national trade is with a European Community that Turkey longs to join, and Istanbul, conduit for most of it, is this nation’s most West-wed city.

At the same time, the metropolis is the gateway to emerging Black Sea countries and looms large to the hopes for investment, technology and know-how of would-be reformers and entrepreneurs in the formerly Soviet, Turkic-speaking countries of Central Asia. Nowadays, it is easier to fly to Tashkent or Samarkand from Istanbul than from Moscow.

As a city where most people take Islam about the same way most Italians take Catholicism, Istanbul is a paramount symbol of the modern, west-looking Turkey. It is an Islamic pioneer that is admired, or reviled, by neighbors in Iran and the Middle East.

One day early next century, Turkish legislators may join members of the European Parliament in Strasbourg. Meantime, Istanbul is growing at the rate of two Strasbourgs a year.

Like its new denizens, Istanbul brims with ambition and contradiction. The city’s largest individual taxpayer is an old Armenian madam who runs a factory-sized brothel. In 1980, there was only a single luxury hotel. Today, Istanbul has more five-star hotel rooms than there were in Barcelona last summer.

It is an exotic, tumultuous Third World city with First World pretensions: 1 million cars and 15,000 parking spaces, by the mayor’s count. Everybody knows the huge, exotic Covered Bazaar. But shoppers also jam La Galleria, a new mall that is an exact copy of one in Houston, Tex., down to the Baskin-Robbins, Kentucky Fried Chicken and the ice-skating rink.

Shares on the Istanbul stock market still change hands in waterfront teahouses. But not far away a huge trade center is being built in the fond hope that one day Istanbul, halfway between New York and Tokyo as bulls and bears fly, will blossom as a new center in the 24-hour world financial market.

Constantine’s city, called Constantinople until it became Istanbul in 1926, clung to the lovely, strategic Bosporus shores. It had 1 million residents in the 11th Century. But after a procession of wars, fires and earthquakes, only a fraction of that huddled behind city walls when the Ottomans finally ousted the old emperor’s Byzantine heirs in the 15th Century.

During centuries of rule by sultans, Constantinople acquired a reputation as a city of breathtaking paradox: incredible opulence at the palace versus unspeakable squalor for most city folk. By the time Istanbul became the first capital of the new Turkish republic in 1923, it was a picturesque but dowdy backwater.

“When I was a boy, this was a city of 600,000--refined people, including lots of Greeks, Armenians and Jews who had been living here for centuries. Everybody knew everybody and how much sugar they took in their coffee,” said Gulersoy, who is 62.

In the mid-1970s, Istanbul officially covered 98 square miles. But by then, rural mechanization and a succession of development-oriented governments were building a huge wave of internal migration. Population has doubled in the last decade alone. Today’s Istanbul, gobbling land with unquenchable thirst, is now 110 miles east to west at its widest point, covering 2,300 square miles. One new middle-class housing development is planned for 40,000 units by century’s end.

Exponential growth puts enormous strain on the infrastructure and services and cruelly damages the environment. Land, sea, air and people all pay the price of progress: Millions live in slums with little light or water; the storied Golden Horn--the isthmus that divides the city and was the harbor for the fleets of Byzantine emperors and Turkish sultans--is inky; in summer, reservoirs dry up; in winter, the air is fetid from soft coal heating the city. The mayor says the city needs 125,000 new housing units a year but can afford only about 15,000.

Much of what is new about Istanbul is ugly. The city’s graceful old skyline of spires, domes and palaces is slashed like a vandalized canvas by the often disproportionate bulk and thrust of new office buildings and hotels. Zoning? What zoning?

A ride from European Istanbul across one of two new bridges to Asia to seek out the limits of the city somehow contrives to become a visit to both the future and the past. The future is cookie-cutter apartment blocks stamped, row upon row, scars on fresh-scoured hillsides alongside super highways so new their road signs haven’t yet caught up with them.

The suburbs are a poor man’s dingy, almost monochromatic wasteland: brutal traffic, awesome potholes, mud interspersed with half-finished three- and four-story buildings of raw concrete, storefronts with apartments above. Every other shop sells building supplies. Motes of color are the jaunty mini-buses that are the lifeline, and the purgatory, of newcomers to Istanbul.

“Live such a life that even the gravedigger will cry,” reads the injunction on one bus, pursued by an impressive cloud of black exhaust smoke.

The past is the two country-folk customers of Yuksel Azakli, a young, open-air butcher in a baseball cap. Azakli, a new immigrant, had been feeding 19 sheep in a pen alongside the road a few minutes before. Now, one of them, a plump white ewe, hangs dead from a makeshift meat rack. Azakli is dressing the carcass under his customers’ sharp-eyed gaze.

“Go to a butcher and who knows what he gives you? This way we are sure. We buy the whole thing,” said one of the customers, as Azakli coiled small intestine like a clothesline. Weighed on a scale as rustic as the customers, the ewe changed hands for around $65.

Along the pitted butcher’s road, the sense of the city begins to recede but not the urban appeal. More than an hour by car from the city lights, the new suburb of Sultanbeyli begins, although as real estate salesman Seufi Elmas puts it: “For people coming from the east, this is Istanbul.”

Sultanbeyli recently was a village around a dairy farm, population 3,741 in 1985. A new sign proclaims the population as 82,289. At his office with a view of a new graveyard on newly paved Main Street, Mayor Ali Nabi Kocak laughs shortly at the absurdity of numbers.

“We put that sign up in 1990. The population today is probably between 125,000 and 150,000. There’s never enough money, but I’d say 90% of the people get basic services.” There are seven new schools and a 100-bed hospital. Townsfolk have banded together with public subscriptions to build schools, electric relay stations and 58 mosques, the mayor said.

People from every province in Turkey have moved to Sultanbeyli. The attraction is simple, said the mayor: “People have everything they need in the countryside except work. They come to Istanbul because it is the only place where there are factories. The only way to stop them from coming is to build jobs in the countryside.”

Kocak is a bearded and bulky former Muslim priest and carpet shop owner who runs Sultanbeyli with old-fashioned righteousness. No liquor is sold in Sultanbeyli, there is no gambling. And, the mayor said, there is almost no crime. “He who takes bribes is cursed in the eyes of God,” reads a big sign at city hall.

Elected in 1989, Kocak became the first mayor of the Muslim fundamentalist Rafah Party in the Istanbul area. There are now eight others in the 38 municipalities of once rural Istanbul province as it is being swallowed by the big city.

Country ways, though, including deep-seated Muslim tenets, are proving resistant to urbanization. As the tide of immigrants moves from the vast plains of Anatolia to the Turkish west, it may not be big city Istanbul that liberalizes conservative country folk, but vice versa. “Because of the influx, Istanbul has lost its personality. It is becoming Anatolia. The newcomers’ village culture is becoming dominant,” said Kocak.

So quickly is their city changing that the people of Istanbul seem inured to surprise. Not long after the old Galata Bridge was towed off into the sunset, a gobble of bulldozers moved in on one of the city’s major thoroughfares and ate it all up.

Now it is impossible to get across the street for blocks in either direction. A cavernous hole, seemingly as broad as the Bosporus, will one day resolve itself into the new old city’s first major subway line.

Times special correspondent Hugh Pope contributed to this report.