During the first half of the 20th century, the Vieille-Mer, like most of the former Seine-Saint-Denis rus, was gradually channeled and then covered, as part of hygenist policies and flood risk management. Today, new urban policies aim to reveal this hydraulic heritage, in order to strengthen its ecological and social function. From the heart of Saint-Denis to the heights of Georges-Valbon park, this route invites you to follow in the footsteps of the Old Sea and to better understand the project of its rediscovery.