This work aims at describing Istanbul and its particular feature, namely the stretch of sea that crosses it. It is a huge sea dividing and unifying at the same time, a sea that permeates the bowels of the city, shaping it, giving it breath, at the same time making it float. This sea constitutes a big source of relief for the inhabitants of Istanbul and is also a favored point from which to observe the world. It represents a crossroad between two universes; it is a "limitation" and a "starting point" at the same time. This is where my reflexion begins.