the istanbul canal will run five kilometers parallel to the bosphorus straight, connecting the blackea to the mediterranean. it will provide a new route for oil tankers, in the government says that will boost revenue. but as julia hahn reports from istanbul, critics say the multibilli-dollar project is an environmental disaster in the making. reporter: these are the first scoops of dirt of a colossal project that could change istanbul's geography forever. a man-made waterway that will flow through new urban districts with new settlements for hundreds of thousands of people canal istanbul is the largest infrastructure project turkey has ever seen. it has long been a dream of president rep tayyip erdogan. >> today we are starting a new page in the's's history of turkey development -- in the history of turkey's development. we are adding a new step to the path of progress for our country and the strengthening of our nation. reporter: but the controversial project is pitting turkey president against istanbul's mayor. >> we are against it because it threatens istanbul completely. it's wat