The Petite Ceinture is a disused metropolitan railway line in encircles the centre of Paris. Built in 1852 and operation until 1934, the Petite Ceinture route still shapes Paris along with the Boulevard Peripherique and the more recent tramway lines. A geographical line that encompasses the city but at the same time marks a boundary between the centre and the suburbs. Today this division is more blurred by the continous expansion of an increasingly vast and jagged city. Following its path still allows us to adopt a point of view on an urban fabric far from tourists and in continous transformation in which modern architecture mixes with the forms from the past. And it is precisely through this constant mutation that the Petite Ceinture runs and whose abandonment had allowed the development of small corners of spontaneous and untamed nature: everything around it moves and alters frantically, while inside everything appears motionless.