An orange or an egg? Determining the shape of the world

Thirty-two years ago the young Nicholas Crane, who would go on to become one of England’s most esteemed television geographers, set out to woo a young woman by spiriting her off to the unfailingly romantic landscape of Chimborazo and Cotopaxi. The couple spent their high-altitude idyll walking the hills in hobnail boots, making river passage in dugout canoes and boarding a Quito-bound steam train through the Andes, run by the estimable Empresa de Ferrocarriles Ecuatorianos.

Their journey had its moments: at one stage both parties were to be found at 13,000 feet, crusted with ice and huddled overnight from the gales inside a pair of plastic rubbish bags; they then got themselves lost for a while among a wilderness of huge and very active volcanoes. But eventually they fetched up at the old ruined Inca fortress of Ingapirca, by now safe and sound and contentedly engaged to one another.

Moreover, the young Crane — who wisely travelled with the classic Inca history by John Hemming in his rucksack — found himself imbued with a lasting fondness for Andean exploration and adventure.