Arouca is a small town in the mountains east of Porto, best known for two things: one of the world's longest pedestrian suspension bridges, and a geopark full of giant trilobite fossils. Neither is especially well-known outside Portugal, which makes the place feel like a genuine discovery.
The 516 Arouca bridge stretches 516 metres across the Paiva gorge and hangs 175 metres above the river. Walking across it is genuinely nerve-racking — the mesh floor lets you see straight down to the water. It opened in 2021 and for a time held the record as the world's longest pedestrian suspension bridge. The gorge itself is spectacular, and the bridge sits at the end of the Passadiços do Paiva, a well-marked riverside trail that runs 8.7 km along the Paiva River through forest and rock formations.
The Arouca Geopark is a UNESCO Global Geopark and contains some of the largest trilobite fossils in the world — some over 90 cm long — exposed in slate outcrops in the mountains. There's a small but worthwhile museum in town, and guided tours go out to the fossil sites themselves. If you have any interest in geology or deep time, this is worth the detour.
The town itself is quiet and fairly ordinary. There's a Cistercian monastery — the Mosteiro de Arouca — that has been here since the 10th century and contains a notable collection of baroque art and a royal tomb. Worth an hour.
Arouca is easiest reached by car from Porto (about 70 km). It makes a good day trip, though if you want to do both the bridge and the Passadiços do Paiva trail properly, an overnight stay makes more sense.