List of longest suspension bridge spans Other crossings of the Turkish Straits: Bosphorus Bridge Fatih Sultan Mehmet Bridge Yavuz Sultan Selim Bridge Marmaray Tunnel, undersea rail tunnel connecting the Asian and European sides of Istanbul. Eurasia Tunnel, undersea tunnel, crossing the Bosphorus for vehicular traffic, opened in December 2016. Great Istanbul Tunnel, a proposed three-level road-rail undersea tunnel.