Bardenas Reales

Where it sits. The Bardenas Reales occupy roughly 42,000 hectares of southeastern Navarre, in the Ebro depression between the river itself and the foothills of the Pyrenean pre-range, close to the towns of Tudela, Arguedas, Valtierra and Carcastillo. Rainfall here runs under 400 millimetres a year and evaporation is high, so the vegetation gives out and the geology takes over: a badland of clay, gypsum and sandstone cut into gullies, mesas and isolated pinnacles by flash floods that arrive a handful of times a year and do a decade's work in an afternoon. The result looks nothing like anywhere else in northern Spain, and the abruptness of the transition — green Navarre ends and this begins within twenty minutes of driving — is part of the effect.

Three landscapes, not one. The park divides into three sectors. El Plano, in the west, is a raised plateau given over to dry cereal farming and is the least interesting to a visitor. La Blanca, in the centre, is the classic Bardenas: pale, almost lunar terrain of soft marl and gypsum, entirely bare, dissected into ravines and studded with erosional remnants. La Negra, to the south and east, is higher and darker, capped by resistant limestone and sandstone and thinly wooded with Aleppo pine, its edges falling away in long escarpments. The emblem of the whole park is Castildetierra, a solitary clay pinnacle in La Blanca standing some 20 metres high beneath a protective sandstone cap, visibly losing material every wet season and certain to collapse eventually.

Who owns it and who shoots at it. The Bardenas are common land. Their usufruct belongs to the Comunidad de Bardenas Reales, an association of 22 entities — municipalities, the Roncal valley, the Monastery of La Oliva — whose grazing rights are documented from the medieval period, and shepherds still bring flocks down from the Pyrenean valleys in a transhumance that runs each September. Since 1951 a substantial area in the north has also been a live-fire range operated by the Spanish air force, a long-running source of local protest and legal challenge. The range closes roads during exercises, and the park's own bulletins carry the dates. UNESCO designated the whole area a Biosphere Reserve in 2000, and it has been a natural park under Navarrese law since 1999.

On screen. The Bardenas served as the Dothraki Sea in the sixth season of Game of Thrones, filmed in autumn 2015, and it is the location most often confused with the desert scenes shot in Almeria for the same production. The Navarrese material supplies the pale, open plains crossed by Khal Moro's khalasar with Daenerys Targaryen as captive, and the wide riding shots around Vaes Dothrak. It is not the only production to have used the terrain — the Bardenas have stood in for Central Asia, Mexico and outright fiction in feature films, and they turn up constantly in car advertising, which is why the landscape often feels familiar to people who have never heard of the park.

Wildlife and the quiet case for going. For all the emptiness, the ecology is rich and specialised. The steppe holds Dupont's lark, one of Europe's most localised birds, alongside little bustard, stone-curlew, black-bellied sandgrouse and Montagu's harrier; griffon and Egyptian vultures work the escarpments of La Negra; and the gypsum soils carry an endemic flora that exists almost nowhere else in Spain. Early morning is the productive time for all of it, and it is also the only tolerable time in summer.

Where to sleep. One hotel sits inside the boundary, a low complex near the Arguedas entrance, with a scatter of rural accommodation in the surrounding villages. Most visitors base themselves in Tudela, twenty minutes south, which has a Romanesque and Gothic cathedral with an exceptional Last Judgment portal, a surviving Jewish quarter, and the vegetable markets that make the Ribera of Navarre worth eating in — artichoke, borage, white asparagus and piquillo peppers in their proper seasons. Arguedas itself is known for the cave houses cut into the marl bluff above the village, a few of them still lived in.

Getting there and doing it properly. The main entrance and information centre are at Arguedas, off the NA-134, with a second access near Carcastillo. A signposted unpaved circuit of roughly 34 kilometres runs through La Blanca and is drivable in an ordinary car in dry conditions at low speed; after rain the clay turns to grease and the tracks are closed outright. Cycling the loop is popular and mountain bikes can be hired locally. There is no water, no shade, no fuel and patchy phone signal inside the park, and leaving the marked tracks on foot or by vehicle is prohibited. Summer temperatures pass 40°C and the light flattens everything at midday. March to May and October to November are the seasons that make the journey worthwhile, and dawn and the last hour before sunset are when the badlands acquire the modelling that the middle of the day removes.