This study focusses on spatial knowledge acquisition among Ukrainian children, temporarily displaced as a result of a war and newly arrived in the Netherlands. As part of a place-based citizen science project, we conducted two sketch mapping sessions, one before and one after the project, to explore youth's conceptualization of the environment following a three-month residency in the new city, and to assess the impact of a two-week citizen science project on place discovery. Methodologically, we investigate the semiotics of sketch maps supported by individual interviews, and characterize types of knowledge and experiences reflected in the data. The presented work suggests that the sketch map representations capture the physical, emotional, and social contexts of youth's interaction with the new environment, while place-based citizen science provides an opportunity for direct and indirect spatial knowledge acquisition and enrichment of the city image with new meanings, contributing to place discovery.