Parque Natural de las Hoces del Alto Ebro y Rudrón

The Hoces del Alto Ebro y Rudrón Natural Park covers 46,474 hectares in northern Burgos province, between the Páramos and Sedano districts. Here, before the Ebro reaches the flatlands of Miranda and La Rioja, it has carved a limestone canyon system with drops exceeding 200 metres in certain stretches. The vertical walls of Upper Cretaceous rock, estimated at 80 million years old, form a corridor where light shifts in tone with every passing hour. At the base of the cliffs, karst springs feed pools of clear water that hold a near-constant temperature of around 10 °C year-round. The scent of damp moss and limestone fills the gorge floor, especially at dawn, when river moisture condenses on the rock faces.

The confluence of the Ebro and Rudrón rivers at Valdelateja marks the park's geographic heart. From this point the canyon narrows and griffon vulture colonies — some 400 breeding pairs recorded by the Junta de Castilla y León — occupy ledges on both sides of the gorge. It is one of the largest colonies of this species on the Iberian Peninsula. Egyptian vultures (present April to September), peregrine falcons and eagle owls also nest here. Riparian woodlands of poplars, willows and alders line the riverbanks and, in autumn, paint the gorge floor in deep yellows and ochres. The contrast against grey rock produces a landscape that wildlife photographers rank among the most photogenic in inland Spain. At night, the absence of light pollution allows clear views of the Milky Way from anywhere in the canyon.

Orbaneja del Castillo, tucked beneath a rocky amphitheatre rising 100 metres, is the park's most visited village and one of the most photographed in Castilla y León. Its urban waterfall, fed by the Cueva del Agua — a karst spring draining an underground aquifer stretching several kilometres — drops directly over limestone houses before reaching the Ebro. Flow varies with the season: in spring it peaks after snowmelt from the páramos, with discharge that can exceed 50 litres per second. In summer the flow shrinks to a trickle barely wetting the rock. Other settlements such as Pesquera de Ebro, Cortiguera and Escalada preserve traditional limestone architecture with flagstone roofs and offer rural accommodation in restored houses. Burgos Romanesque heritage appears in chapels like San Pedro de Tejada (12th century, with a portal sculpted with over 30 figures) and the Escalada collegiate church, whose cloister retains historiated capitals.

The waymarked trail network exceeds 120 km and links the canyon's main viewpoints. The route between Pesquera de Ebro and Orbaneja del Castillo (14 km, moderate difficulty, 4–5 hours) follows the cliff edge with unbroken river views and passes the vulture nesting sites, where birds can be watched from barely 30 metres away. For those who prefer the water, the Ebro is navigable by canoe on several sections from April to October, with class I–II rapids suitable for beginners. The most popular stretch, from Valdelateja to Pesquera de Ebro (8 km), takes 2–3 hours with stops. Sport climbing sectors at Valdelateja and Orbaneja offer over 80 routes from 6a to 7c on compact limestone.

In winter, fog rising from the river wraps the cliffs and cuts visibility to a few metres, creating a hushed atmosphere that entirely transforms the canyon experience. Villages empty out and the only sound is the Ebro striking rock. This is the season landscape photographers choose for capturing the canyon without human presence. The park's geology also includes active tufa formations — porous rock structures growing millimetre by millimetre where calcium-carbonate-laden water precipitates — visible at secondary waterfalls along the Rudrón. These tufas are classified as a priority habitat under the EU Habitats Directive, making the park a reference site for karst geology in southern Europe.