Take part in the City Nature Challenge at the Citadelle
On the occasion of the City Nature Challenge, Fort Saint-Nicolas invites visitors to discover its hidden biodiversity — a natural oasis in the heart of Marseille undergoing transformation. This walk encourages reflection on the preservation of fauna and flora within a confined space marked by military history and the footprint of the port.
The City of Marseille is participating alongside hundreds of other cities worldwide in the City Nature Challenge, an annual global citizen science competition where cities come together in a friendly contest to work toward a common goal: better understanding all the living species that inhabit our cities.
To take part in the challenge, simply use the iNaturalist platform or app and upload your observations of fauna and flora found at the Citadelle (and throughout the city)!
More information about the City Nature Challenge 2025 in Marseille