 For Humboldt, a key question was the influence of climate on the development of these civilizations.When he published his "Vues des cordillères", he included a color image of the Aztec calendar stone, which had been discovered buried in the main plaza of Mexico City in 1790, along with select drawings of the Dresden codex and others he sought out later in European collections.His aim was to muster evidence that these pictorial and sculptural images could allow the reconstruction of prehispanic history.