The trail goes through a narrow valley, alongside which is Ribeira de Quarteira, and climbs up to Paderne Castle, a public interest monument. The river is at its best preserved state here, and you can find some traditional water management infrastructures.
Paderne Castle is one of the best national examples of rammed-earth military constructions. Dating back to the 2nd century (Almohad Caliphate), it was one of the first castles taken during the Christian Reconquista. The castle is an irregular polygon, with a single, massive Albarrana tower. Take note of the colour: an intense ochre, which contrasts with the deep green of the Mediterranean scrubland.
The Castle Bridge, with its Roman features, dates to medieval times and was built to support to the castle. It has 3 arches and 2 cutwaters shaped like a triangular prism. Near the bridge you can find the remnants of a water mill (Alfarrobeira Mill), as well as the old miller’s house and the oven.
In the dark side of the valley grows a scrubland mainly composed of junipers, strawberry trees, Mediterranean dwarf palm, mastic trees and various kinds of lianas. Carob and olive trees line the trail and, on the rivershore, you can find the only living population of a particular kind of small daffodil (Narcissus willkommii). The sunnier area of the valley has a more scattered scrubland, with beds of rockrose, thyme and lavender. Here you can find the Centaurea occasus, a thistle species endemic to the Algarve’s Barrocal.
Next to the Castle’s weir you can see a water mill, dating to the Arab period. The local wildlife also makes good use of the water; there are signs of the presence of otters, skunks and hedgehogs, as well as various amphibious and countless aquatic birds (e.g. the grey heron and little egret) and passerines (wagtails, nightingales, warblers and finches, among others). The riparian vegetation includes typical species of pluvial riverlands: reeds and ash, oleander and tamarisk trees.
Location: Paderne Castle
Circular trail: yes
Distance: 3,2 km
Average duration: 1h30
Cumulative elevation gain: 117 metres D+
Type of path: somewhat rocky dirt paths
Start of the trail: 37º 09' 36.40'' N 8º 12' 03.80'' W