Ribeira de Sor stream is the main hub of this route, framed by the constant presence of the cork oak. It begins in the Ribeirinha Area, we cross by the original pedestrian bridge. We follow the river and start climbing up to Ervideira, this small elevation is covered by cork trees. We descend the mountain and return to the riverbank. We now come across some old mills, and the Tramaga mills, whose hydraulic mechanics allowed them to transform the cereal grain into flour for bread. Here the sound of water mixes with that of birds singing. In the egress we cross the lovely Parque da Marginal.