Drive the eight kilometres up the dead-end valley and work out that the spa is in a cirque with no way on

Take the waters, which the Romans were already exploiting here

Work out what the 19th century did to this valley and how many people the spa supported

Walk up to the ibones above the resort, which are glacial lakes at altitude

Come in winter for the Panticosa-Los Lagos ski area on the other side of the valley

Eight kilometres up a dead-end valley from Panticosa, in a glacial cirque ringed by peaks, is a thermal spa built in the 19th century on a Roman-era exploitation of the same springs. The 19th century was its high point — the village itself is mostly buildings from that period, when Panticosa held nearly nine hundred people on the back of the spa. The waters come out of the mountain in a place where there is nothing else, and the ibones, the high glacial lakes above the resort, are a short and very steep walk further up.

Panticosa: A Roman Spa in a Glacial Cirque

Walk up the Ossoue valley from the barrage d'Ossoue on the GR 10 as far as the grottes Bellevue at about 2,400 m, and find the fork there where the path splits — right for the Petit Vignemale and the refuge, left for the glacier

Sleep at the Refuge Bayssellance at 2,651 m on the east side of the Hourquette d'Ossoue — the highest and oldest guarded refuge in the Pyrenees, built in 1899 and rebuilt in 2003, with 58 places in summer — and find the ogival stone vaulting kept from the original building

Stop at the grottes Bellevue on the GR 10 at about 2,400 m, the Russell caves you can walk to, then from the glacier look up at the higher ones and measure by eye the twenty-odd metres of ice that has gone from under them since Russell had them cut

Cross the glacier d'Ossoue — the largest glacier on the French side of the Pyrenees, 45 hectares in 2011 and down to 25 by 2022 — to the base of the pique Longue, and finish the last stretch to the top on easy rock

The Vignemale is the highest summit of the French Pyrenees at 3,298m, and the normal route crosses the Ossoue glacier from the Bellevue caves on the GR10 to the foot of the Pique Longue. Count Henry Russell made the first winter ascent on 11 February 1869 with the guides Hippolyte and Henri Passet, sixteen hours' forced march from Gavarnie, slept on the summit in a lambskin bag in August 1880, and then had seven caves cut into the mountain between 1881 and 1893 — the last, the Paradis, at 3,280m just below the top.

The Vignemale: The Highest of the French Pyrenees and Russell's Caves

Get to a Pyrenean valley with a known territory and watch the cliffs from below

Work out that it is not after the marrow — it swallows bone whole, up to twenty centimetres at a time

Look for the bone-dropping sites, where the same rock slabs are used again and again

Learn the silhouette: the long wedge tail and narrow wings separate it from griffon at a great distance

Find out where the Cantabrian birds came from and why Aragon supplied them

The quebrantahuesos — bone-breaker — is the only bird in the world that lives almost entirely on bone. It does not put its head into a carcass like other vultures; it waits until the carnivores, crows and griffons have taken everything soft, then takes the skeleton. It swallows pieces up to twenty centimetres whole, and carries larger bones to height and drops them on rock to shatter them. About 75% of its diet is the bones of wild and domestic ungulates. The Pyrenees hold the core European population, and birds from Huesca have been used to reintroduce it to the Cantabrian range.

The Bearded Vulture: The Bird That Eats Bones

Walk the full 240m length of the station building and count some of its 365 windows

Find the section preserved as a small museum, documenting the station's role smuggling Nazi gold and hiding refugees between 1942–1944

Look for the plaque honouring Albert Le Lay, the French border guard called "the Schindler of Canfranc" for helping refugees escape

Walk a stretch of the disused rail line heading toward the sealed French border tunnel — the international route has been closed since 1970

Canfranc International station is 241 metres long with seventy-five doors on each side, built to the design of the engineer Fernando Ramírez de Dampierre and modelled on 19th-century French palace architecture. It took five years and was inaugurated on 18 July 1928. International services stopped between 1945 and 1949 over a falling-out with the French government, and then ended altogether on 27 March 1970 when a French freight train derailed and brought down the L'Estanguet bridge on the far side of the border. A new passenger station opened on 15 April 2021 in two rehabilitated freight sheds, and in 2023 a luxury hotel opened inside the old building itself.

Canfranc: The Belle Époque Station on the Border

Walk in to the Sarradets refuge the normal way, from the col des Tentes over the port de Boucharo on the border and round under the cliffs, rather than up the échelle des Sarradets out of the cirque, which is the steep route — and finish over the col des Sarradets at 2,589 m with the Brèche directly above you

Walk through the gap at about 2,807 m and pace its width — forty metres, with the France-Spain frontier running along the whole of it, so there is no single point where you cross — then look up at the sixty-odd metres of wall still standing above your head

From the Spanish lip of the Brèche, look south into the Sobrarbe in Huesca and work out the three things this gap opens the way to: the Ordesa canyon dropping away below, the Mont Perdu off to the east and the Taillon on your right hand

On the way back down, look across to the Fausse Brèche and find the abri Gaurier under the pic Bazillac — the cave in the cliff that the abbé Ludovic Gaurier fitted out in 1906 and the Club alpin français improved in 1911, and the only shelter up here until the refuge was built

The Brèche de Roland is a gap 40 m wide and about 70 m deep cut clean through the rim of the cirque of Gavarnie, and the border between France and Spain runs along its whole width — the Pyrenees National Park on one side, Ordesa y Monte Perdido in Aragon on the other. The legend has Charlemagne's nephew Roland opening it after Roncevaux, not by cutting the rock but by trying to destroy his sword Durandal against it; when the blade would not break he threw it, and the story says it ended up in a cliff at Rocamadour, three hundred kilometres away. Roncevaux is a hundred kilometres west of here, which makes the name doubly poetic. The usual way up is from the Sarradets refuge at 2,587 m, and old snow sits in the gap well into the summer.

The Brèche de Roland: Roland's Sword Cut in the Cirque Wall

Walk the classic 14 km loop from the Lac de Bious-Artigues past the six lacs d'Ayous — Roumassot, du Miey, Gentau, Castérau, Paradis and Bersau — and find the one where the north face of the Pic du Midi d'Ossau stands whole in the water; the boundary of the Pyrenees National Park is at the far end of the Gentau, so the lakes themselves are outside it

Take the cable car up from the Lac de Fabrèges at 1,240 m, then ride the 10 km of 500 mm track to the Lac d'Artouste, looking straight down into the Soussouéou valley the whole way and through the 315 m Tunnel de l'Ours — the line was laid in 1920 to haul cement up for the dam, and only put to work carrying tourists in 1932

Walk up to the foot of the pic and stand in the cirque de l'Embarradère, the 200-hectare hollow between the Moundelhs and Peyreget arcs that is the actual crater of the Ossau volcano — then look up and pick out the notch of the Fourche, 180 m below the summit, that separates the Grand Pic from the Petit Pic

It was probably first climbed in June 1790 by a shepherd from the Aspe valley with one or two others, sent up by the surveyor Louis-Philippe-Reinhard Junker to plant a signal for the commission that was drawing the French-Spanish frontier; Junker recorded sighting that signal the next day. The first ascent anyone wrote down was Guillaume Delfau's, on 3 October 1796, with his guide Mathieu.

The Ossau Valley: A Volcano's Remains, the Lacs d'Ayous and the Artouste Train

Drive the full 40 km of the Aspe valley from Escot up to the col, and ignore the signs for the 8.6 km tunnel that has taken the traffic off this road since it opened on 7 February 2003 — the old pass road is the quiet one now

Stand on the frontier at the col by the Ermita del Pilar, the one building up here, and work out what the pilgrims coming up the Via Tolosane from Oloron-Sainte-Marie were facing: 840 km still to Santiago, down into Aragon on the Camino aragonés

Walk a stretch of the waymarked pilgrims' way down from the col towards Urdos, and find the abandoned works of the Pau to Canfranc railway in the valley beside it — opened in 1928 and shut after a goods train brought down the Estanguet bridge on 27 March 1970

Walk Borce for its medieval houses and the ecomuseum room on the pilgrim road, then cross to Etsaut and look up at the Fort du Portalet clamped to the gorge wall — known as the fort d'Urdos although almost all of it stands in Etsaut

Walk the Chemin de la Mâture above Etsaut, the ledge cut straight into the rock in 1772 so that trees from the bois du Pacq could be brought down to be made into ships' masts, and work out how a mast was got along it

The Somport sits at about 1,632m on the Spanish border where the Aspe valley opens into Aragon, and the Roman road up to it, the Via Tolosane, was the most popular of all the crossings for pilgrims heading to Compostela until the 12th century, when Roncesvalles became the safer choice. The Vandals, Alans, Suebi and Visigoths all came the other way through it in the early fifth century. The Aspe below is still wild country, and for a long time it was the refuge of the Pyrenean brown bear.

The Col du Somport: The Pilgrims' Pass Above the Aspe Valley

Drink from the Fuente de Gándara, which is what the whole municipality is built on

Work out that this is the smallest municipality in Galicia at 2.31 square kilometres

Find the Palacio del Agua, the old bottling plant for Aguas de Mondariz

Look at the old Gran Hotel and work out who was coming here in its period

Find out why the spa was made a separate municipality from Mondariz in the 1920s

Mondariz-Balneario covers 2.31 square kilometres and has about seven hundred inhabitants, which makes it the smallest municipality in Galicia — and it exists because of the water. The Peinador family developed the springs from the 19th century into a resort that drew the Spanish and Portuguese elite, and the town was separated from Mondariz in the 1920s specifically so that the spa could govern itself. What is left is the Gándara and Troncoso springs, the Palacio del Agua bottling plant and the shell of the old Gran Hotel.

Mondariz-Balneario: The Smallest Municipality in Galicia

Take the waters at the Baños de Fitero, in use since the Roman settlement of Tudején

Go into Santa María la Real, founded in 1140 on a donation from Alfonso VII by monks from Escaladieu

Find out what Raymond of Fitero raised at Calatrava, and that he never got this monastery back

Work out what the name means and which two kingdoms and two dioceses met here

Find the older bath structure underneath the 19th-century spa buildings

The name Fitero means frontier, because in the 12th century the monastery here sat on the line between Castile and Navarre and between the dioceses of Calahorra and Tarazona. Saint Raymond of Fitero founded the monastery with Cistercians from the abbey of Escaladieu in the high Pyrenees, on a donation from Alfonso VII in 1140. He then raised a Cistercian militia, took it to Calatrava, and out of it came the Military Order of Calatrava. He never got his own monastery back: his monks were beaten and driven to Calahorra, a second Cistercian community arrived in 1161 under a new abbot, and Raymond died in exile at Ciruelos. Downstream on the Alhama are the baths, in use since Roman Tudején, now a working spa on hot mineral water with a Moorish bath structure underneath the 19th-century buildings.