Where once the wheels of ore carts rattled through the landscape, today an extraordinary scenery unfolds. The industrial heart of the Basque Country has been transformed beyond recognition. Former quarries, like El Ostion and Las Carmenes, have filled with water to become picturesque ponds surrounded by green meadows. Picnic areas with tables and grills have been set up here, and clean waters are now stocked with trout and carp. Amidst this pastoral landscape, herds of local cattle and horses graze, while farmhouses dot the hillsides.
This is the so-called βGreen Route of the Iron Mountainsβ (VΓa Verde Montes de Hierro-Burdinmendi), the longest in the province of Bizkaia. This initiative has breathed new life into the old railway lines that once served the mining industry. Today, itβs over 40 kilometers of well-maintained trails and branches, perfect for walking and cycling. Travelers will find authentic tunnels, old loading stations, and artificial lakes, and the route itself links the natural biotope of the Triano mountains with the stunning La Arena beach.
The journey begins at the FEVE railway station in TraslaviΓ±a, where kilometer zero is located. From here, the trail follows the Kolitza River, dipping twice into the coolness of tunnels measuring 87 and 147 meters long, and crosses the river via a wooden bridge. Near El CastaΓ±o, you can see the remnants of the Catalina mine with ore roasting furnaces and the Los Herreros tunnel, which was hand-carved into the rock. Further along, you’ll encounter the Sopuerta Abentura adventure park and the La AseΓ±a rest area, a perfect spot to take a break.
Heading towards Galliarta, the path runs over footbridges above the BarbadΓΊn River and past former loading platforms. This is also where the Basque Mining Museum is located, offering an impressive view of the Concha II quarry from its observation deck. Other highlights include the 150-meter illuminated El Sobaco tunnel. At the end of the main route, the trail splits. One branch leads to the sea, joining the Itsaslur “Green Way,” where you can admire the dunes and watch birds at La Arena beach, and in PobeΓ±a it connects with the famous Camino de Santiago pilgrimage route. The other branch heads to the river’s mouth, providing access to the Bilbao suburbs.
Every step on this land is a brush with history. Todayβs pedestrian route follows paths laid out in the 19th century by British entrepreneurs who built them to transport iron ore to the ports of the Cantabrian Sea. It was here that the famous football cheer “alirΓ³n!” was born. When British engineers discovered a rich deposit, they would mark it with a sign reading “all iron,” which local workers embraced as a good luck chant. This story is just a small part of the regionβs rich industrial heritage.
You can deepen your journey into the past by visiting the Mining Interpretation Center in PeΓ±as Negras or the colorful workersβ village of La Arboleda. Itβs easily reached by funicular from Trapagaran, which has been operating since 1926. Former minersβ barracks have been replaced with rest areas and marked trails. For touristsβ convenience, there are bike rentals, horseback rides, and even guided tours along the 14.5-kilometer stretch.
Reaching the starting points is easy: you can drive to the La Arboleda recreation area or take suburban trains to TraslaviΓ±a station. The project continues to grow, with plans for new connections to river NerviΓ³n cities such as Sestao and Barakaldo. All this is possible thanks to the efforts of local authorities and enthusiasts, who have devoted more than a decade to preserving this unique legacy for future generations.
