You need no qualifications to be a South American explorer other than an instinct for stubbornness and survival. The ruins the Incas and other pre-Columbian civilisations left behind are scattered over thousands of miles of still largely uncharted territory, particularly in the Eastern Andes where the mountains fall away dramatically towards the Amazon.

Twenty years ago, Hugh Thomson first set off into the cloud-forest on foot to find a ruin that had been carelessly lost again after its initial discovery, his introduction to the curious and confusing world of Inca exploration. This is the story of his subsequent adventures as he travelled to the most remote Inca cities, both in the cloud-forest and in the jungle, and of the great explorers who had first hacked their way into the unknown with machete and whose footsteps he followed.

Many of these explorers’ stories have never been told, like that of Robert Nichols, killed looking for the mythical ‘Paititi’ (a temple-site in the Madre de Dios which has acquired the same lure for explorers as the original El Dorado had for the conquistadors). Hugh Thomson also talks to the most remarkable of modern explorers, Gene Savoy, who has discovered many impressive sites in recent years, including Espíritu Pampa, the last refuge of the rump Inca court after the Spanish Conquest.

Thomson weaves into the narrative the history of the Inca Empire up to those very final days, and gives a fascinating account of what they left behind, the remnants of a remarkable civilisation that is still only partially understood. The Incas left no written history and almost all that we know about them comes from the often biased accounts of Spanish conquistadors and from the work of archaeologists. Their legacy has also been wilfully distorted by a legion of New Age advocates, who often superimpose on the Incas a spirituality that they feel the modern world has lost - with the result, Thomson argues, that we have lost sight of who they really were.