The best circular walk from Manteigas is to the Poço de Inferno waterfall and back, which takes around four hours. Most of the paint-mark trail signs are missing or faded, but it’s a straightforward route with some gorgeous views. The walk starts in the Zêzere valley bottom, from the small bridge and picnic area reached down the steep road behind the turismo in Manteigas.
Cross the bridge, turn left (signposted “Leandres”) and walk for 500m along the road, past the recycling plant, before turning right onto a clear forestry track. Keep straight on, ever upwards through the woods – the first yellow paint sign is on a tree on the right-hand side (6min) and there isn’t another until you reach a ruined white house in a clearing (45min) marked with the words “Matas Nacionais”.
Five minutes’ walk after the house is the only turn off the main path – to the left (with paint marks before and after the turn). In another fifteen minutes the path ends at a bend in a tarmac road. Walk uphill (there’s a yellow paint mark almost immediately) and it’s twenty minutes further up the road to the Poço do Inferno, “Hell’s Well”, where the Leandres River pours down the narrow gorge into clear pools overlooked by viewing platforms.
To return, follow the minor road around past the falls, heading back towards Manteigas. This road actually runs steadily down to Caldas de Manteigas, though this would be a long (8km) and unnecessary return to Manteigas itself. Instead, after an hour, at a large water tank by the right-hand side of the road (there’s also a white house, just before a small bridge), turn right down an ancient track – walled in parts – which drops in zigzags through the trees. Ultimately, there are several divergent paths, but as long as you keep going downhill you’ll end up in the group of houses by the Albergaria Berne (another 30min) – from where it’s a steep fifteen-minute climb into Manteigas proper.