Do you look for that missing house key the same way as your children or parents? Visual search is a ubiquitous task in our daily lives, and thus an important topic of study. One way to study visual search which approximates daily tasks is with free eye movements in (controlled) natural scenes. However, eye tracking data is expensive to collect, often resulting in small and potentially biased samples of university students. We here present on our work collecting gaze data from several thousand participants of a wide age range, obtained with a research-grade eye tracker, in ongoing collaboration with the NEMO Science Museum in Amsterdam. Visitors performed a single trial of a free eye movement task, in which they searched for a low-contrast ‘x’ or ‘+’ hidden within a collage stimulus. Targets could be in one of six locations which were designed to have various levels of difficulty. We present our findings on viewing patterns from thousands of participants, and how their demographics may affect accuracy and saliency. We furthermore discuss the benefits and pitfalls of such a citizen science approach to eye tracking, concerning data quality, hardware options, public engagement, and collecting and estimating the validity of demographic data without an experimenter being present. Our openly available dataset aims to provide high-quality, wide age range, gender-balanced, eye movement data from one of the largest samples to date.