For thousands of years, human beings ignored a large part of the planet's territories, landscapes and inhabitants, and on maps the unknown regions were called Terra incognita. Even in 1840, the seabed was a complete mystery. Thirty years later, scientists continued to defend that the sea covered the poles and in 1900 no one had yet managed to reach the stratosphere. And yet, all these gaps became the stimulus our ancestors needed to unravel the secrets of the Earth that amazed and terrified them in equal measure. In pursuit of knowledge they made countless mistakes, sometimes brilliant, often strange, but always fascinating. In this magnificent essay, Alan Corbin offers us a revealing story of ignorance as the engine of human curiosity that awakens our thirst for knowledge and transforms our vision of the world.