As an Enlightenment scientist, Alexander von Humboldt was continually observing, measuring, and describing the world. If he made major discoveries, nowadays he is mostly recognized as a father of biodiversity and a figure of interculturality and interdisciplinarity. The Humboldtian vision of the cosmos, characterized by its unity in diversity, is close to our ecological and planetary thought. Interestingly, his approach combines science and aesthetics, with domains as different as cosmopolitics, physical description of the world, and geopoetics. But in all these issues, he always manages to separate what is scientific from other considerations. An actualization of this vision may be crucial for our own society facing the challenges of the planet