Spain celebrates the 10th anniversary of the City Nature Challenge with bioblitzes in various cities
The global citizen science event, City Nature Challenge, invites people to explore and document urban biodiversity from April 25 to April 28
This 2025, the City Nature Challenge (CNC) celebrates its 10th anniversary, and Spain once again joins the global event that mobilizes thousands of people to record the biodiversity of their surroundings through iNaturalist. Over four days, from April 25 to 28, citizens, naturalists, students, and environmental professionals will venture out to observe and photograph nature in their cities, contributing to the knowledge and conservation of biodiversity.
The CNC is an international competition between cities, aiming to record as many species as possible within a four-day period. Since its launch, it has grown to involve over 690 cities and nearly 2,000 local organizers worldwide.
A global challenge with a local impact
To commemorate this special edition, various cities and towns in Spain are organizing their own bioblitzes, inviting the community to venture into the countryside, parks, gardens, and natural spaces to record wildlife. The collected data not only fosters interest in biodiversity but is also integrated into GBIF (Global Biodiversity Information Facility), contributing to research on conservation and climate change.
On behalf of the organizers of the City Nature Challenge in Spain, we encourage everyone to join this 10th edition of the challenge by exploring nature and celebrating biodiversity in their surroundings. You can check the projects and participating cities on the Natusfera Blog or the CNC 2025 umbrella project. Among the confirmed events in Spain are the following:
- City Nature Challenge 2025: Málaga
- City Nature Challenge 2025 de Sevilla
- Biomaratón CNC 2025: Zaragoza
- Biomaratón CNC Villafruela-Burgos 2025
- Biodiverciutat 2025 – Àrea Metropolitana de Barcelona
- Biomarató 2025: Pla de l’Estany
- City Nature Challenge 2025: El Vendrell – Tarragona
- Biomarató CNC 2025 Crevillent i espais naturals
- Biomarató CNC 2025 Santa Pola
- Biomaratón CNC 2025: El Álamo, Navalcarnero y Casarrubios del Monte
- Biomaratón CNC Colmenar 2025
- Biomaratón CNC 2025: Getafe
- Getafe Biomaraton Primavera 2025 Iberozoa Madrid
- Biomaratón CNC 2025 Guadalix de la Sierra
- City Nature Challenge 2025: Madrid
- Biomaratón City Nature Challenge 2025: Rivas Vaciamadrid
- Biomaratón CNC 2025: Pamplona /Iruña
How to participate
- Download the iNaturalist app or use Natusfera, the Spanish portal of the iNaturalist network.
- Make observations: From April 25 to 28, capture photos and sounds to document plants, animals, fungi, and other wild organisms.
- Share your observations: Submit your observations before May 4.
- Help with identifications: From April 29 to May 4, review and help identify species shared by other participants.
- Follow the results: The event results will be announced on May 5.
During these days, anyone can participate simply by heading out to the streets, parks, or nearby natural spaces and uploading their observations of wild organisms.
About the City Nature Challenge
The City Nature Challenge is a global event aimed at promoting citizen participation in science, particularly in the study of urban biodiversity. Since its inception in 2016, the CNC has engaged over 500,000 people worldwide and recorded millions of observations..
The organizers of the initiative are the California Academy of Sciences and the Natural History Museum of Los Angeles County, in collaboration with various institutions and local organizers.
Follow the event on social media using the hashtags:
#CityNatureChallenge #CNC2025 #10AñosCNC #Biodiversidad #CienciaCiudadana