When Turkey's transport minister announced the launch of one of the most contested construction projects in Turkey – a third bridge over the Bosphorus – on 29 May, he said the date of the announcement had been chosen because it marked the anniversary of Istanbul's conquest by the Ottomans.
Now many fear that it might spell its final defeat.
Recep Tayyip Erdogan, Turkey's prime minister, who once said that a third bridge "would mean the murder of the city", has thrown his weight behind the 4.5bn Turkish lira (£1.6bn) project and the bridge is now predicted to open as early as 2015. But environmentalists, urban planners and many Istanbul residents are furious at the plan, arguing that it will create more traffic, increase the number of vehicles in Istanbul and spell an end to the few remaining green areas and urgently needed drinking water reservoirs that have so far resisted the urban sprawl. Then there's the lack of thorough geological research in a major earthquake zone.
Plans for a third bridge over the Bosphorus have circulated since the early 1990s, with its proponents claiming that another motorway across the strait would ease traffic congestion and generate big profits.
However, Akif Burak Atlar, secretary of the Istanbul chamber of urban planners, said: "The third bridge is a real estate project, not a project to ease traffic. Experience from the previous two bridges shows that land speculators will be the ones to profit."
Research also shows that traffic is only likely to increase. According to a report published by the chamber, the number of cars crossing the Bosphorus increased by 200% only one year after the first bridge was opened in 1973, and from the opening of the second, Fatih Sultan Mehmet bridge in 1988, until today, the number of motor vehicles crossing the strait has risen by a staggering 1,180%, while the number of people actually using the bridge only rose by 150% in the same period.
Atlar argues that Istanbul urgently needs to expand its public transport system to rely more on trains and ferries. "The money spent on the bridge could be used to build a coherent metro network," he said. "Istanbul needs a fast, comfortable and well-connected metro network to keep people from using their cars."
Environmentalist groups also warn that the project will endanger the remaining green areas to the north of Istanbul. Some 80% of the Northern Marmara highway project will cut through forest areas. Several animal and plant species native to the region would be wiped out, and the fragile ecosystem would be in serious danger. Water reservoirs supplying the city, already too few, would be at risk of drying out or becoming too contaminated to use.
"A lot of trees will be cut down," said Yusuf Yavuz, an environmental activist. "This will put a claw into the land of Istanbul."
Another problem created by the highway and the third bridge would be the rapid acceleration of urban sprawl in a megacity that is already growing uncontrollably and lacking both the infrastructure and the resources to sustain such rapid growth. Researchers add that migration to Istanbul would increase substantially, negatively impacting on the social fabric of the city. Between 1975 and 2010 Istanbul's population grew from roughly 2.5 million to an estimated 13.3 million people.
Atlar said: "It is one of the basic rules of urban planning that the creation of main roads will attract settlements, services and further infrastructure around them." Claiming that Istanbul had been abandoned to the mercy of the real estate and construction sectors, he added: "If the government was able to prevent uncontrolled growth, this would not be such a problem, but Istanbul spreads like a cancer cell."
