Help Philadelphia take on the world while you connect with nature in the 2024 City Nature Challenge. Beginning on Friday, April 26 at 12:01 am in each time zone, the City Nature Challenge runs through Monday, April 29, 11:59 pm. The global event, co-organized by San Francisco’s California Academy of Sciences and the Natural History Museum of Los Angeles County, calls on current and aspiring community scientists, nature and science fans, and people of all ages and education backgrounds to observe and submit pictures of wild plants, animals, and fungi using the free mobile app iNaturalist. From Friday, April 26 to Monday, April 29, participants can upload their observations to the app, with identifications happening from Tuesday, April 30 to Sunday, May 5. Final results will be announced on Monday, May 6.