President Erdogan oversaw a ceremony inaugurating the $3 billion Yavuz Sultan Selim Bridge, which is touted by its Turko-Italian developers as the world's broadest suspension bridge at 58.4 metres (192 feet) wide.

The toll bridge, spanning 1,408 metres (4,620 feet) over the Bosphorus, is built in the style of New York's Brooklyn Bridge and boasts pylons higher than the Eiffel Tower.

It features 10 lanes, including two rail lines. At 322 metres (1,056 feet), officials say the bridge's towers are also the tallest in the world.

"When man dies, he leaves behind a monument," Erdogan told a crowd of thousands waving Turkish flags at the opening ceremony on the shores of the Bosphorus next to the bridge.