This stage, dominated by Pateira de Fermentelos, takes you from Segadães to Sangalhos, almost always through rural and forest roads, far from the traffic of the many localities that involve this natural ex-libris. The Pateira, considered the largest natural lagoon in the Iberian Peninsula, must be understood as an ancient marine arm where three rivers flowed independently: the Cértima, the Águeda and the Vouga, before the formation of the Ria de Aveiro, approximately from the 16th century. The first stretch of the stage follows the left bank of the Vouga, flanked by agricultural fields, to Eirol, where it flexes southward, crossing some small settlements. In Requeixo, you will find the bed of the river Águeda, which crosses over the magnificent Roman bridge of Requeixo, but you can make a detour to the right before crossing the bridge to explore the northern area of Pateira and visit the Park of Requeixo. It accompanies the Águeda along some meters, always through fields of cultivation, going after meeting the margins of Pateira and the much sought after Park of Óis da Ribeira. It then crosses a small patch of eucalyptus, finding shortly after the extraordinary Espinhel Park, with its two unique viewpoints, completely surrounded by water except for the small corridors that give them access. Take a break to observe the magnificent avifauna that occurs here and explore PR1 - From Pateira to Águeda trail, which leads you to discover the secrets of this "enchanted lagoon". Always heading south, it finds the Cértima river bed and riparian forest, following its course until Sangalhos.