Some 5km south of Thusis, the main road – followed by postbuses on their way to Bellinzona – plunges into another extraordinary ravine, with sheer rock walls barely 10m apart rising some 500m from the bed of the foaming Hinterrhein. This Via Mala (Evil Road) was first constructed in 1473, various improvements since then resulting in a web of bridges spanning the gorge. At one point, you can descend 321 steps to the valley floor to see both the ancient original road and the bridges lined up way overhead (April–Oct daily 8am–sunset; Fr.3).

The gorge opens up 8km south of Thusis at the small farming village of ZILLIS (Ziràn in Romansh), worth a stop to investigate the painted wooden ceiling in its small St Martinskirche (Baselgia Sontg Martegn). Located on what was formerly the main route between Konstanz and Milan, the first village church dated from the sixth century, but it was later overbuilt by the current Romanesque building, which still sports a huge external mural of St Christopher, patron saint of travellers. The polygonal choir dates from 1509, but complete renovation in 1940 means that the interior is today brand shiny new, in stark contrast to the painted wood-panelled ceiling which is original twelfth-century but almost perfectly preserved.

The ceiling is divided into 153 square panels, each of which sports a different, remarkably clear image (there’s a handy stack of mirrors by the door to save you cricking your neck). Running all the way around the edge is the sea, with angels in all four corners representing the four winds. The interior panels are devoted to stories from the life of Christ, which start at the east (choir) end and run from north to south row by row until you reach the west (door). The sixth row from the choir, for instance, shows the Three Wise Men and the Holy Family’s flight into Egypt on a donkey; the ninth row begins with Christ’s baptism in the Jordan and ends with the miracle of turning water into wine at Cana; four rows below it is Jesus entering Jerusalem on a donkey; two rows below that is the kiss of Judas. Christ crowned with thorns is the last of the biblical scenes, since the final row, instead of depicting the Crucifixion and Resurrection, is instead inexplicably devoted to scenes from the life of St Martin, implying that the unknown artist was, for some reason, unable to complete his intended story-cycle.

Some 6km south of Zillis, the main road bends westwards, but if you have your own transport (or take the bus from Andeer, a few kilometres south of Zillis), you might want to detour up the remote Val Ferrera, laced with waterfalls and flanked by 3000m-plus peaks. The lonely road penetrates for some 25km through barely half-a-dozen widely spaced hamlets, ending up at Juf, a cluster of farmhouses which, at 2126m, claims the title of the highest permanently occupied village in Europe.

The main road from Zillis continues through the deep Rheinwald forest to the dourly picturesque village of SPLÜGEN, with a jumble of traditional slate-roofed houses, a tourist office (081/650 90 30, www.splugen.ch), a year-round campsite (081/664 14 76) and four hotels, including the Pratigiana, an old smugglers’ haunt (081/664 11 10, fax 664 12 88; b). The Splügenpass (2113m), 10km south of the village and reached via a twisting minor road, marks the Italian border; postbuses use this road to reach the town of Chiavenna, 30km south, from where postbuses run back into Switzerland up the Val Bregaglia to St Moritz. From Splügen itself, the main road climbs west in the shadow of the giant Zapportgletscher, one of the sources of the Rhine, to the San Bernadino Pass. These days the pass route is undercut by a long road tunnel open year-round, which feeds down into the long Valle Mesolcina on the south side of the Alps, completely Italian speaking but still in the territory of Graubünden. The main road coils down out of the mountain air, becoming a fully fledged motorway alongside the hilltop Castello di Misox, at roughly the point where vines, fig trees and chestnut forests spring up all around, giving a hint of the lushness of the gorgeous Canton Ticino spreading out to the west. The Ticinese capital, Bellinzona, lies 24km further south.