Mount Serantes (451 m), due to its parallel location to the coast, is a magnificent lookout point for the Abra and the entrance to the Port of Bilbao. For this reason, it has been used for the installation of military buildings for surveillance and defence.
The two main parts of the fortifications are the Serantes Fort and the guard tower on the hilltop, both of which have been declared Sites of Historic and Cultural Interest.
The fortifications comprise two main parts: the Serantes Fort and the guard tower on the hilltop.
The tower is the earlier of the two: it was completed in 1881 to defend against sieges from the Carlists. It is built in a square design using dressed stone blocks, and features two levels plus the rooftop, which served as a lookout point and was flanked by sentry turrets.
Lookouts at its top could monitor both banks of the Nervión estuary, the beacon hills Mount Oiz and Mount Sollube, the Peñas del Duranguesado ridge behind them and even as far as the Cabo Villano headland on clear days. It has recently been restored and is open to visitors.
The fort was built in 1882 as part of a programme to reorganise the defences on the river estuary outside Bilbao. It takes the form of an irregular pentagon, with a surface area of around 8500 m2.
Subsequently, the batteries were installed due to the entry of the United States into war with Spain on April 25, 1898, after the mysterious explosion of the American battleship "Maine" on February 16, 1898 in the Bay of Havana, in the midst of the war of Cuban independence. The Spanish military then feared that there might be a North American invasion of the peninsula, and fortified much of the Cantabrian coast, including the natural shelters of the mouth of the Nervión estuary such as the Serantes, Punta Lucero and La Galea. Later, between the First and Second World War, the location of these facilities was reconsidered as dangerous in the event of an attack, as they were close to urban centres.
On the other hand, there are still customs from another era, which are reflected in the traditional Cornites Romeria held since the XIXth century every Easter Monday.
Mount Serantes is part of the NORDIC WALKING SANTURTZI CENTRE. The Santurtzi Tourism Office offers 38 km of signposted routes of different levels along its slopes, with an incomparable view over the Abra and the coast.
Following the restoration of the tower, guided tours of the fortifications and the natural areas on the hillside are now available.