Alexander von Humboldt, Researches, concering the institutions & monuments of the ancient inhabitants of America. London, 1814.

The great naturalist Alexander von Humboldt launched the mature phase of his career by traveling throughout Latin America in 1799-1804 with his friend Aimé Bonpland, observing everything from meteor showers to birds, recording natural phenomena and the character of the inhabitants, and publishing his findings in thirty volumes over the course of several decades. In the Andes he was particularly fascinated by mountains and volcanoes.