Go in on the mine train through the old gallery, which is the only way in

Find the helictites — eccentric stalactites that grow sideways instead of down

Find the draperies, translucent sheets of calcite hanging like flags from the roof

Work out how it was found: miners cutting for zinc and lead broke into a cavity that blew air at them, which is what soplao means

Work out the scale of what is behind the lit section: about twenty kilometres of cave, of which four are open

El Soplao was cut into by accident during zinc and lead mining, and soplao was the miners' word for a karst cavity that blew a strong draught when they broke into it. It runs to about twenty kilometres of which four are open, and what makes it exceptional is the formations: helictites — eccentric stalactites that grow sideways and defy gravity — and translucent draperies hanging from the roof. You go in on a mine train, through a working gallery, into a cave the people who found it had no idea was there.

El Soplao: The Cave the Miners Found by Accident

Learn to spot an indiano house: the palm in the garden is the giveaway

Find the school, the fountain or the cemetery an indiano also paid for in the same village

Work out where the money came from — Cuba, Mexico, Argentina — and what it cost to get it

Go into one that is open as a museum or a hotel and look at what was brought back

Work out why so many are on this particular stretch of coast and not inland

From the 19th century into the 20th, people left the Asturian and Cantabrian coast in enormous numbers for Cuba, Mexico and Argentina, and a proportion came back rich. What they built is unmistakable: brightly painted mansions with galleries and towers, set in gardens planted with imported palms — a palm in the garden is the reliable sign — often alongside a school or a fountain they also paid for, because returning as a benefactor was part of the point. Whole villages along this coast are shaped by them.

The Cantabrian Indiano Houses

Go into El Capricho, built 1883–85, and work out how much of the later Gaudí is already in it

Find the sunflower tiles running round the outside and work out why they are there

Walk up to the Sobrellano palace and pantheon by Joan Martorell

Find the former Pontifical University by Domènech i Montaner on the hill

Work out how a village this size acquired three major Catalan architects, and where the money came from

Antonio López y López, first Marquis of Comillas, made a fortune in Cuba and brought Catalan architects home to his village on the Cantabrian coast. The result is extraordinary for a place this size: Gaudí's El Capricho of 1883–85, one of his earliest works and one of only three he built outside Catalonia; the Sobrellano palace and pantheon by Joan Martorell; and the former Pontifical University by Lluís Domènech i Montaner. It is effectively a Catalan Modernisme colony dropped into a Cantabrian fishing village.

Comillas: A Catalan Modernisme Colony in Cantabria

Go into El Pindal and find the mammoth among the thirteen bison and eight horses

Look for the red dots, lines and club-shaped signs painted beside the animals

Walk out across the Rasa de Pimiango, the raised wave-cut platform above the cave, to the cliff edge

El Pindal opens in the sea cliffs near Pimiango, at the far eastern end of Asturias, and its paintings have been known since 1908. Most are on the right-hand panels: thirteen bison, eight horses, a hind, a stag and a mammoth, with red dots, lines and club-shaped signs among them. The cave has been protected since 1924 and part of the UNESCO World Heritage Site of Altamira and the Palaeolithic cave art of northern Spain since 2008. Only the eastern half is open to visitors; access to the western half is restricted.

El Pindal: A Mammoth on the Sea Cliffs of Asturias

Drive the N-621 through all twenty-two kilometres of it and work out that you cannot see the tops of the walls from the road

Stop and look up at limestone faces over 600 metres high

Work out its strategic point: this is the only corridor from the Cantabrian coast into Liébana

Look for vultures and eagles on the updraughts, and chamois on the rock — 6,350 hectares of the gorge is a special protection area for birds

Find out who used this road in the 19th century: British travellers, climbers and hunters on their way to the Picos

The Deva has cut twenty-two kilometres of gorge through the Ándara massif between Panes and Cillorigo de Liébana, which makes it the longest defile in Spain, with near-vertical limestone walls some of them over 600 metres high — so high that from the road you cannot see the top. It is the only way in to Liébana from the Cantabrian coast, which is why the narrow N-621 runs through it. In the 19th century it was the route British travellers, mountaineers and hunters took to get at the Picos de Europa.

La Hermida: The Longest Gorge in Spain

Walk the Black Pool and Clear Fountain trail (7km) from Bárcena Mayor into the park's beech and oak forest

Walk the Fuente Clara path along the Argonza river, the second of the two main routes starting directly from the village

Find Bárcena Mayor's open wooden balconies (corredores) and stone façades, protected as a Historic-Artistic Site since 1979

Hike to the Alto de la Guarda viewpoint for a wide view over the whole Saja-Besaya massif

Bárcena Mayor is the only inhabited settlement inside the boundary of the Saja-Besaya natural park, and it sits within the Saja National Hunting Reserve as well. It was declared a historic-artistic ensemble in 1979 as a homogeneous and well-preserved example of montañesa architecture — stone houses with wooden balconies and deep overhanging eaves, built for a wet mountain climate. Waymarked trails leave from the edge of the village straight into beech and oak forest, which is what the whole valley is: one of the largest continuous deciduous woodlands in southern Europe.

Bárcena Mayor: A Mountain Village in the Saja Forest

Drive the narrow mountain road into Tresviso, cut into the Picos de Europa cliff face — one of the most remote villages in mainland Spain

Find the natural limestone caves above the village where Picón Bejes-Tresviso is aged for two to four months at 5–10°C

Taste Picón directly from a producer in Tresviso — a blend of cow's, sheep's and goat's milk unique among Spain's blue cheeses

Continue to Bejes, the cheese's other namesake village, on the descent back toward the coast

Picón Bejes-Tresviso is a blue cheese with protected designation since 1994, cured in natural caves in the Picos de Europa exactly as Cabrales in Asturias and Valdeón in León are cured — the same mountain, three names, three appellations. The paste is white with blue-green veining from Penicillium growing in the cave air. Tresviso itself has around fifty inhabitants, and the oddity is that although it is in Cantabria there is no road to it from Cantabria: the only road in comes from Asturias, and reaching the rest of your own region by car means about forty kilometres.

Tresviso: The Cave-Aged Blue Cheese of the Picos

Go into Santa María de Valverde and work out that nothing here was built — it was dug out

Find the anthropomorphic graves cut into the sandstone outside, shaped to the body

Find the Romanesque bellcote added to the outside of a church that has no outside walls

Drive the valley and find more of them — Arroyuelos, Cadalso, the hermitages at Villamoñico

Work out why here: the Ebro valley sandstone is soft enough to carve and hard enough to stand

Valderredible in southern Cantabria is where the Ebro valley's soft sandstone allowed people to cut churches directly out of the rock rather than build them — hollowed naves, carved columns, and anthropomorphic graves cut into the stone outside. Santa María de Valverde is the best of them, probably the Santa María la Sotarraña named in the cartularies of Covarrubias and Santa María de Aguilar between the 10th and 13th centuries, with a Romanesque bellcote added on the outside later. Rock hermitages like Los Ventanos at Villamoñico are scattered across the same valley.

Valderredible: Churches Cut Into the Rock

Walk the open plaza between the dome and the auditorium and work out that the plaza is the actual building

Find out how Avilés got it: a gift from Niemeyer to the Principality after the Prince of Asturias Award of 1989

Look from the centre back across the ría at the steelworks and see the contrast Niemeyer was working against

Go into the medieval old town, which is a completely different Avilés a few hundred metres away

Work out why he rated it above everything else he did in Europe

Oscar Niemeyer won the Prince of Asturias Award for the Arts in 1989, and on the twenty-fifth anniversary of the awards he gave the Principality a project. What he gave them was a set of white curves on the industrial riverside at Avilés — a dome, a tower, an open plaza — set against a heavy steelworks town and a medieval old quarter. It opened officially on 26 March 2011. It is the only Niemeyer building in Spain, and he said himself it was the most important thing he ever built in Europe.