"Parkopolis," the life-sized board game, was designed to promote conversation and science, technology, engineering, and mathematics (STEM) learning. We investigated whether this exhibit also prompted questioning. Caregivers' and children's STEM-related question-asking was compared between Parkopolis (i.e., experimental group) and a STEM-themed control exhibit. Groups (N = 197) of children and caregivers visiting two exhibits in a museum were observed. Observations revealed that caregivers and children asked more mathematical questions in Parkopolis than in the control. Caregivers also asked more spatial questions in Parkopolis. In addition, when all STEM-related question topics (i.e., mathematical, spatial, and scientific thinking) were combined, children asked more STEM-related questions in Parkopolis than in the control. Finally, children responded to a higher proportion of caregivers' questions in Parkopolis than in the control. Factors that promoted this question-asking in Parkopolis, such as signage and the interactive nature of the exhibit, can inform the design of other informal learning spaces to promote question-asking.