A framework to my journey was provided by the exploits of the great Andean adventurers of the past, one of the most influential of whom was the German scientist Alexander von Humboldt.
A photogenic drive (or tour-bus ride) here is the Seven Lakes route, which winds for 110km between a series of lakes surrounded by Andean peaks and beech and myrtle forests enlivened by red anemone-like notros and yellow michay flowers.
And when the lightning arrives – caused by heat, humidity and Andean winds, and accompanied by roaring thunder – it explodes in all directions burning jagged bolts into your retina.
Then there are the salt flats, the lagoons, Death Valley, the flamingo reserves … San Pedro's dusty streets may be thronged with tourists, but it is still an appealing, easygoing huaso (cowboy) town: one-storey adobe buildings, a leafy main square with an archetypal Andean church; an excellent archaeological museum.
On reaching Colombia, I concentrated my attention on the magnificently preserved Andean colonial towns, uncanny reminders of a bygone Spain.
A herd of llamas eyed us warily, and a flock of Andean geese circled, then decided to land.
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.
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.
01722 718444, discoveradventure.com On this tour through Argentinian and Chilean Patagonia you'll experience the wonder and scale of one of the wildest places on the planet, and see everything from whales and penguins to glaciers and Andean peaks.
By four in the afternoon the city, ringed by its Andean peaks, was quieter, so Stewart and I, robbed of connections with London, marched out of the bronze doors down the centre of the deserted streets to our hotels, our hands in the air.
