This article studies the conceptions of the interior of the Earth held by Portuguese elementary school children and senior citizens. Several studies were conducted regarding conceptions related to Earth sciences, such as rocks, minerals, earthquakes geological time, and Earth structure. Most of these studies involved students enrolled in compulsory education, some involved higher education students, several involved teachers, and only a few involved adults. The majority of the results showed that many misconceptions are held by people of all ages. Similar (...) results were found in this study, as both children and senior citizens revealed several misconceptions. The research resorted to a questionnaire based on a drawing task so as to find out the way that children and senior citizens imagine the structure and composition of the interior of our planet. A comparison between children’s and senior citizens’ drawings was made, as well as a comparison between those drawings and the historical models of the internal structure of the Earth. We found that only a small number of children and even a smaller number of senior citizens recognize that the interior of the Earth is organized in concentric layers. They assume that soil and water are a common part of the internal composition of our planet. Similarities between the drawings and the historical models were identified, particularly similarities related to Gautier’s model, which accepts the possibility of the existence of life in the interior of the planet as it happens on its surface. (shrink)