Grab your backpack and join the National Geographic Society and the National Park Service at the Santa Monica Mountains BioBlitz, a 24-hour event from May 30 to May 31, noon to noon, when teams of scientists, naturalists, community leaders, students and the public will join forces to discover and inventory the biodiversity in the nation's largest urban national park.

Part scientific endeavor, part festival and part outdoor classroom, the BioBlitz's goals are to record as many living organisms in the Santa Monica Mountains as possible in 24 hours, to increase awareness of the diverse species in this urban setting and to better understand how to protect the natural environment in the future.

Following the species count will be the Celebrate BioDiversity Festival, on May 31, from 1 p.m. to 6 p.m., with music including the Banana Slug String Band, talks, displays, and opportunities to explore more of the park, to talk with the scientists and to see them in action.

"Explorers" of all ages are needed. Paramount Ranch will serve as "base camp" for both the BioBlitz and the festival. Registration for the BioBlitz is required. To learn more about the Santa Monica Mountains BioBlitz or to register, log onto www.nationalgeographic.com/bioblitz or call (800) 638-6400 ext. 6186.