This is the first year that San Diego will be participating in this growing event. Only 3 years old, now more than 50 cities from all around the world are taking part. Help show how species-rich San Diego is by observing and uploading as much as possible during this event, April 27-30, 2018.
http://citynaturechallenge.org/

San Diego Natural History Museum is the sponsor for San Diego and they have already created a project that will collect all the observations. The link below has some great information about the event.
https://www.inaturalist.org/projects/city-nature-challenge-2018-san-diego-county

That same day there will be a bioblitz going on in Balboa Park and that will also collect the observations into both projects.
https://www.inaturalist.org/projects/2018-balboa-park-bioblitz