Help the San Francisco Bay Area show the world how biodiverse our region is by making as many observations of as many species as possible April 27-30! You can also help with IDs for other people's observations to increase our species count, come to a bioblitz, or even hold your own event! For a full list of organized events, click here.

Which city on Earth has the most nature and the most engaged residents? The City Nature Challenge 2018 (April 27-30) will help us find out! More than 60 cities on five continents are asking residents of and visitors to these urban areas to explore nature all around them and document the species they find. 

Building on the success of the first City Nature Challenge in 2016 between San Francisco and Los Angeles, and the 2017 City Nature Challenge across 16 US cities, the event founders, the California Academy of Sciences and the Natural History Museum of Los Angeles County, have expanded the event around the world.

Last year over 126,000 observations were logged in 5 days by over 4000 citizen scientists, representing more than 8500 species in the United States! That works out to one observation about every 3 seconds of the City Nature Challenge! What will we find this year, when we look all over the world?