The diversity of life, apart from biological diversity, also includes our diversity as human beings: our wealth of knowledge, practices, beliefs, values and forms of social organization. But all this is, in fact, inextricably linked with nature: over the centuries, our ancestors have developed ways of interacting with the environment by assigning spiritual values to certain species and places. These are the so-called “sacred natural sites”: natural areas recognized as holy by indigenous and traditional peoples, and natural areas recognized by religions as places for worship and remembrance. Gonzalo Oviedo, IUCN’s Senior Advisor for Social Policy, has been involved in collecting information about these sites and helping improve their protection. He explains how much we know about sacred sites and how much more we still need to learn.