On Saturday 21 October 2023, we opened the doors of our European Space Astronomy Centre (ESAC), in Villanueva de la Cañada (near Madrid), to host an ESA Open Day. With a full programme of talks and activities, the event featured tours, hands-on laboratory activities for children and get-togethers with science communicators, ESA astronauts and experts. More than 1800 people, both adults and children, had the opportunity to deepen their knowledge of what we do every day.