© 2019, © 2019 Fundacion Infancia y Aprendizaje. The concept of nature frequently appears in the literature, and yet it has rarely been explained. One way of understanding it makes reference to the degree of human intervention, creating a classification on a continuum from totally natural to non-natural environments. In order to identify the empirical categories into which this continuum is organized, two studies were carried out. In the first, 99 Spanish participants evaluated 150 photographs in accordance with their degree of naturalness in order to obtain a set of 50 photographs. In the second, 50 Spanish and 48 Mexican participants ordered the photographs in accordance with their own personal criteria. The results show that people organize landscapes in accordance with the presence or absence of buildings, and that each of these two categories comprises a further three subcategories. This fact could be useful when studying the impact of these environments on aspects such as connectedness or well-being.