Stage 4: Polientes - Orbaneja del Castillo

The dirt track now becomes asphalted just outside Arenillas de Ebro. After crossing the village, you turn off it beside the 12th century Romanesque church of Nuestra Señora de la Asunción. Follow the road to Villota de Elines, 1.5 km away. You then leave the village, taking a dirt track that begins beside the church and heads towards San Martín de Elines, first among pastureland and crop field and then among gall oaks.

If you have enough time, you can visit the collegiate church of San Martín de Elines in the village square. It was originally a 10th century Benedictine monastery with Mozarabic influences. Its Romanesque church was built in the 12th century. The cloister, which houses beautifully-carved 16th century sarcophagi. The exterior is stately: a circular tower and a set of marvellous corbels.

The route then follows a path that leads down to the river and to Barrio de Abajo, with good views of San Martín de Elines and its collegiate church, the moorland of La Lora and Arroyuelos. The Nature Trail continues straight, leaving the bridge over the Ebro on the left leading to Arroyuelos, passing a washing place. The route approaches the spectacular Ebro canyon, whose presence can be intuited by the narrowness of the walls enclosing it. From the path you can see the last foothills of the La Lora moor, and fields with cattle and horses. Continuing along the route, you will enter a gall oak grove, which also contains beech trees.

The route leaves behind an abandoned religious building before reaching Villaescusa de Ebro and its bridge. The site is divided into two neighbourhoods linked by an asphalted road on the right bank of the Ebro. Its church is simple and vernacular, but its architecture is among the most interesting and unaltered churches in Valderredible. In the second neighbourhood, you will continue to cross fields and walls, before entering, after an extensive crop field, an area of gall oaks, beeches and black poplars where the Ebro narrows between the rocky outcrops.

At this point, you can leave the path for a moment to take a simple path to the El Tobazo waterfall. Apart from the waterfall, the karstic nature of these lands means that the carbonate-saturated waters have created a curious geological formation.

On the way back to the Nature Trail, after fording a stream on a concrete bridge, you will reach the Electra del Tobazo power station, where the track ends. Leaving the facility on the left and after going around it, continue on the right bank of the Ebro, along the old road to Orbaneja, through a landscape that combines pedunculate oaks, riverside vegetation and the rocky outcrops that demarcate the river.

After crossing the Vertiente de Cabeza de Pedro stream, the route crosses the Cantabria-Castile and Leon border, entering Burgos. The vegetation soon becomes denser, with holly bushes, pedunculate oaks and a small wetland near a restored pine forest rich in protected bird life.

After crossing the Vertiente de Cabeza de Pedro stream, the route crosses the Cantabria-Castile and Leon border, entering Burgos. The vegetation soon becomes denser, with holly bushes, pedunculate oaks and a small wetland near a restored pine forest rich in protected bird life. At the end of the second meander, a bridle path, leading from the moor, joins the path that runs away from the river and climbs up after leaving behind some magnificent pedunculate oaks. It thus approaches the whimsical rock formations of El Castillo, which gives Orbaneja the second part of its name.

Travellers will be aware here that the vegetation is less dense and the landscape is more open, with the village of Orbaneja del Castillo, the end of the stage, in sight; the centre of the village is reached after crossing a bridge leading to the road. The combination of its spectacular natural landscapes and its popular character make it one of the most beautiful places in the north of Spain: limestone streets, houses with a mountain influence, a Romanesque church, and the karstic complex, with caves that grow in the dolomitic limestone of the Middle Turonian, such as the El Agua, El Barbancho and El Níspero caves. At the end of the second meander, a bridle path, leading from the moor, joins the path that runs away from the river and climbs up after leaving behind some magnificent pedunculate oaks. It thus approaches the whimsical rock formations of El Castillo, which gives Orbaneja the second part of its name.

Travellers will be aware here that the vegetation is less dense and the landscape is more open, with the village of Orbaneja del Castillo, the end of the stage, in sight; the centre of the village is reached after crossing a bridge leading to the road. The combination of its spectacular natural landscapes and its popular character make it one of the most beautiful places in the north of Spain: limestone streets, houses with a mountain influence, a Romanesque church, and the karstic complex, with caves that grow in the dolomitic limestone of the Middle Turonian, such as the El Agua, El Barbancho and El Níspero caves.