The City Nature Challenge is an annual global citizen science event coordinated by the California Academy of Sciences and the Los Angeles County Natural History Museum, that was first run in 2016.
In 2023 Maroondah collaborated with 27 other Councils from across metropolitan Melbourne, along with the Field Naturalists Club of Victoria, the Entomological Society of Victoria, Melbourne Water, University of Melbourne, Latrobe University, Australian Citizen Science Association and Victorian Environmental Friends Network, to represent Melbourne on the global stage as ‘Greater Melbourne’.
In 2024 the Greater Melbourne collaboration now involves at least 25 Councils and 8 other organisations.
Participating cities competed to see who can make the most observations, find the most species, and engage the most observers in discovering the nature that lives in and around their city.