Portal do Inferno e Garra: stay away if you're scared of heights
Portal do Inferno e Garra (Hell Portal and Claw) is a natural viewpoint at an elevation of 984m (3,228ft) above the sea level, located on the boundary of Arouca and S. Pedro do Sul municipalities in the Central Inland of Portugal.
The road to the summit is called Estrada do Portal do Inferno. It’s totally paved but very steep (with some parts up to 11%) and narrow. If you're afraid of heights, it's probably best to keep your eyes forward.
The road is spectacular due to the slopes. The pass is 7.5 km (4.66 mile) long, running from CM1123 road towards EM567 road. Located at the center of the Gralheira Massif mountain range, Portal do Inferno is a unique viewpoint, located amidst the Arada Mountain.
The road offers stunning views of Serra da Arada. It’s one of the steepest mountain roads of the country, with 4 sharp hairpin turns.