This paper describes the design and evaluation of a Multisensory Diorama (MSD) intended as a tool to provide an alternative learning environment for people with intellectual disabilities (ID) in museums. The MSD is designed to be interactive, engaging, and accessible to accommodate the specificities of participants with ID, and to help contextualize and consolidate previous knowledge. The MSD is a portable box with RFID readers, LEDs, a fan, a photoresistor, a button, an Arduino Uno, an MP3 shield, a speaker, and an external battery. The MSD offers two different ways of engagement and interaction via exploration and gamification: visitors can explore the augmented landscape and play a matching game that reinforces their knowledge of the food chain in the forest. In a formative evaluation approach focusing on the accessibility and engagement with the MSD, a study was conducted with 12 adults with ID, who provided valuable feedback to improve the design and make necessary adjustments for future implementations. The MSD proved to be a successful tool for engaging visitors and reinforcing their understanding of the food chain in an interactive and accessible way.