ISTANBUL, Turkey (AP) _ The first bridge connecting Europe and Asia over the Bosporus Strait became Turkey's pride. The second one was practical _ helping ease traffic congestion. But a third one?

Environmentalists and some Istanbul residents say that's one bridge too many.

The Bosporus Strait, a 20-mile waterway linking the Black Sea and the Sea of Marmara, separates European Turkey from Asian Turkey. It twists through Istanbul, running by historic Ottoman castles, mosques and parkland.

The first bridge _ at 3,524 feet, one of the world's longest suspension bridges _ linked the two continents in 1973. The second, 200 feet shorter, opened three miles north of the first in 1988.

The federal government in Ankara has decided to build a third one, but critics say it would destroy precious green space, tower over beloved landmarks and promote car traffic to the detriment of public transportation in this city of 10 million people.

``There's very little green left in Istanbul,'' complained Nurgul Aktas, a visitor at Yildiz Park, which would be covered by supports for the viaducts leading up to the new bridge. ``It's becoming a chain of bridges, one after another. It will look ugly.''

The new bridge's main towers on the European side would stand beside Ciragan Palace, the summer residence of Ottoman sultans from the 17th century to the 19th century.

Yildiz Park, the city's biggest public park along the Bosporus, is home to 19th century Yildiz Palace. On the Asian side, the viaducts would trample several graves at the 18th-century Karacaahmet cemetery.

The government has yet to set a date for construction of the new bridge, to be built 650 yards south of the first. Critics hope to persuade the government to reverse its decision, and propose building a tunnel instead to alleviate traffic while preserving Istanbul's natural and historical riches.

A tunnel would cost about $600 million, roughly equal to the bridge project. But it would be a four-year effort, compared to one year for the bridge. That's one reason the bridge is favored by politicians in Ankara, said Istanbul Mayor Tayyip Erdogan, a critic of the project.

``Because it can be built over a much shorter period, the bridge is a more profitable political investment over the short-run,'' he said. ``The politicians are not considering the needs of Istanbul.''

One of the few vocal supporters of a third bridge, though, is Istanbul's former mayor, Bedrettin Dalan, who was in office when construction on the second bridge began.

``So what if the bridges spoil the beauty of the Bosporus?'' Dalan said. ``You cannot run a city with this mentality.''

A new bridge, though, would not improve the city's traffic flow, said Gungor Evren, professor of transportation at Istanbul Technical University. That can only be done by shifting priorities to mass transit, he said.

``The bridge means more cars, more congestion,'' he said.

Critics blame lobbying by powerful Turkish automakers for Ankara's decision to approve the bridge project.

``They want to put cars onto Istanbul's streets,'' said Sohret Kumcu of the Society for the Protection of Nature. ``But that will worsen the air pollution, which is already the worst in Turkey.''