Istanbul's third bridge connects Europe, Asia
The guide cable will be used to build the Catwalk, which will serve as a working scaffold, and the main cable, before connecting deck slabs.
The third Bosphorus bridge, controversially named after Ottoman sultan Yavuz Selim, or Selim the Grim, and its highways are expected to cost Turkey some $3 billion.
The construction had begun in 2013 and both towers have already been completed. The Asian tower is 318 meters high from the ground, while the European one is 322 meters.