Science and Natural History museums as effective and inclusive environments for young adults' (16 to 25) quality understanding of their world In the growing concern for inclusion in contemporary museums, the young adults represent a crucial concern, whatever their conditions. Knowing that this generation is the demographic segment with the highest interest and openness toward scientific knowledge, science museums are keen to know what sort of impact they can have through their exhibitions to become places of reflective engagement towards the future. Research results from Switzerland, Canada and Mexico will help to go beyond optimistic dreams or readymade assumptions, trying to design some principles for more significant and effective museographies.