The Andes fascinated me long before I got to see them. I had been brought up on the Andean tales of my paternal grandfather, a former railway engineer in Chile and Bolivia. On my mother's side I had ancestors who hailed from the Italian Alps, where so many of the great Andean climbers and adventurers originated. The Andes, as the world's longest continuous mountain range, came to hold the promise of an endless succession of extreme and sublime landscapes.
I planned an ambitious transcontinental route that would begin by following Humboldt and Bolívar through the northern and central Andes and end up with Darwin at South America's southernmost tip. I estimated that it would be six months of near-continuous travelling, largely by bus, but also by train and boat, and even on horseback and on foot.
At Pasto there were numerous indications that I was approaching at last the heart of the Andes, including guinea pig, a famous Andean delicacy, being served at the local restaurants. Overshadowing the landscape was the active Galera volcano, which marked my arrival at a long corridor of volcanoes forming the backbone of neighbouring Ecuador.
In the south of Ecuador I hired a horse and guide to take me on the section of Inca road that leads from the exposed mountain village of Achapullas to the ruins of an Inca palace and temple at Ingapirka, huddled in a deep valley.
The achievement of the Incas' efficient transport system over some of South America's most difficult terrain seemed even more extraordinary when compared with what I would soon find in Peru. For much of the next two months I would be travelling on rickety buses along perilous mountain roads.
The sensational 150km dirt track from the remote northern town of Chachapoyas to Celelendín climbed up to a height of more than 4,000m before descending along a crumbling ledge clinging to a sheer precipice.
The roads remained largely unpaved and vertiginous as I continued along the Andes' spine to the battleground of Ayacucho (in 1824 the Spaniards suffered their final defeat here, which led the independence of Peru), and then down towards the Inca capital of Cuzco. From southern Peru, through Bolivia, and into northern Argentina, my route alternated between the luxuriant jungles on the Andes' eastern slopes, and deserts on the west. Each day brought landscapes more spectacular than the next, though perhaps my most memorable walk was into Peru's Colca Canyon, the deepest canyon in the world. Condors hovered above as I descended a near-vertical slope before ascending the other side to some half-deserted 16th-century hamlets accessible only by footpath.
The autumn was well advanced as I headed south into Patagonia, through near-uninhabited landscapes of lakes, forests and glaciers; the first flurries of snow had begun to fall as I reached the point when the Andes is shattered into a labyrinth of fjords and islands. I finished my journey on a small boat that sails every week from the Chilean port of Punta Arenas to the intimate island town of Puerto Williams, the most southerly community in the world. The exhilarating boat trip, lasting 36 hours, took me across the notoriously stormy Straits of Magellan, through the glacier-lined Beagle Channel, and to places where Darwin had concluded that life barely existed at all. By now I had come to think of the Andes almost in human terms. On seeing them disappear into the choppy, icy seas, I could have been waving a final goodbye to a dear old friend.
