By knowing the shape of our earth we can create maps, survive the oceans, follow rivers, navigate the skies, and travel across the globe. This is the story of our world, of how we discovered what no one thought possible - the shape of the earth.

A thrilling and page-turning account of the first major expedition by data gatherers and qualified observers to interior Peru, to discover the shape and magnitude of the earth. Until humanity discovered this it would be impossible to produce accurate maps and sea charts, without which thousands of lives would be lost, and exact locations of cities, roads and rivers would never be known. This fascinating and dramatic story weaves scientific rigour, egos, funding crises and betrayal with sea voyages, jungles and volcanoes.