Los Angeles ( CNN ) -- By busloads and by church flocks , volunteers throughout the country spent Saturday performing the noble task of cleaning up humanity 's home -- planet Earth . `` The nation 's largest community improvement movement , '' as the volunteer groups are known , got their hands dirty and feet wet as they cleaned walkways and waterways around the United States . Keep America Beautiful -- the nonprofit group that sponsored the Great American Cleanup `` National Day of Action '' -- organized trash-clearing activities in nearly all 50 states , as well as special large-scale events in 10 locales , including Los Angeles . In all , 10,000 volunteers were projected to participate . `` Oh my goodness . The volunteers , the energy , the enthusiasm . To watch the kids learn how to plant a tree was amazing to watch . It becomes theirs , '' said Gail Cunningham , senior vice president of Keep America Beautiful and managing director of the Great American Cleanup . `` It brought nature alive for the volunteers . '' One of this year 's spotlight sites was the namesake waterway of the nation 's second largest city , the Los Angeles River . Saturday 's activities coincided with the Friends of the Los Angeles River 's 23rd La Gran Limpieza , which translates to The Great Cleanup . About 450 people , including 250 from a local Mormon church , collected 400 bags of trash -- including a king-size mattress , an animal skull , and a discarded wheelbarrow -- from one stretch of the river , said Shelly Backlar , the river group 's executive director . Volunteers were bused to cleanup sites . `` People are saying they ca n't believe what they are finding , '' Backlar said . `` Everyone is smiling and really enjoying the river . '' Added volunteer Judy Bloom , 48 : `` I spent a couple of hours picking up several bags of trash and it was primarily plastic , about 90 % . `` There was an element of surprised in respect to how much this is caused by littering , '' Bloom said . The other nine locales for the big-scale cleanups were Oakland , California ; Cocoa , Florida ; Indianapolis ; Cobb County , Georgia ; Hampton Roads , Virginia ; Houston ; Shreveport , Louisiana ; Philadelphia ; and Nashville . Tidying up the country is n't a matter of just `` waving a magic wand , '' said Cunningham . `` It 's understanding each person can make a difference . '' `` Each volunteer for one hour of work is worth $ 21.79 , and we had 5.2 million volunteers last year '' during a period from March 1 to May 1 , she added . `` The United States saved $ 113 million last year that would have otherwise paid government employees . '' Last year 's clean-up activities in 16,500 communities resulted in the removal of 177 million pounds of litter and debris ; beautification of 177,000 acres of parks , public lands and open spaces ; and planting of 166,000 trees and 1.5 million flowers and bulbs , according to Cunningham 's group . Last year , Los Angeles ' La Gran Limpieza collected 25 tons of trash from cigarette butts to `` river treasures , '' as Backlar put it , consisting of shopping carts , a hammock , a sleeping bag and a Barbie doll with dreadlocks . From coast-to-coast , groups were relying on the volunteer spirit of the millennial generation and college students . `` There is passion for engagement and volunteerism from the millennials . They are active . It 's inspiring to see , '' said Cunningham . Christine Flowers , executive director of Keep California Beautiful , said Saturday 's volunteer activities supplement state and local government efforts -- which cost taxpayers about $ 500 million a year -- to address illegal dumping and littering . `` When people get their hands dirty and get engaged , they care more for the environment and their community , '' Flowers said . `` Volunteers learn something new and it gives them passion and fire to better the environment . ''
NEW : ` ` People are saying they ca n't believe what they are finding , '' leader says of trash removal . Saturday 's event is called the ' American Cleanup ` ` ' Day of Action '' Large - scale trash removal is planned for 10 cities , like Los Angeles and Philadelphia . At least 10,000 volunteers are expected to travel across the United States .