San Rafael , California ( CNN ) At 74 years old , Marilyn Price still remembers the first time she rode a bike . `` My father let go of my seat , and there I was on my own , '' she said . Years later , Price realized the power of biking to change lives . During a 1982 mountain biking trip in northern California , Price reached a point on the trail where she could see all of San Francisco . Looking out at the city , she thought of the children she met while volunteering at a soup kitchen there . And it hit her : She wanted to give them the same experience . `` There 's nothing like biking up a mountain and looking behind you to see all you 've accomplished , '' she said . Price has since helped more than 25,000 at-risk children from the San Francisco Bay Area get off urban streets and into nature through her nonprofit , Trips for Kids . Do you know a hero ? Nominations are open for CNN Heroes 2015 . In addition to mountain bike excursions , the group provides bike mechanic training and the chance for young people to earn credit toward their own bikes . Today , Trips for Kids has expanded to 90 chapters around the world , serving more than 15,000 children each year . See more CNN Heroes . CNN 's Allie Torgan spoke with Price about the impact of her efforts . Below is an edited version of their conversation . CNN : For many of the young people in your program , this is their first time on a mountain bike . How do they react ? Marilyn Price : Many of them have never really left the city . To them , life is automobiles and buildings . Everything is concrete . But you bring them where there are no buildings , no cars , it is like , `` Wow ! I did n't know that this exists . '' I think we 're planting a seed that there are alternatives to getting into trouble . They can get on a bike and go to a place that is very much unlike where they live and do something positive . It 's giving them the notion that there is something else . CNN : And their experience goes beyond bike trips . What else do you offer ? Price : The second is our Earn-a-Bike program , where kids in the community come after school . They learn bike mechanics , and while they 're participating they are earning credit . They can use it to buy bikes or parts . They 're buying bikes for themselves , for their parents or siblings . I just love the idea of having them work toward a goal . They 're really learning skills that will help them in the future . The third ( program ) is our bike thrift shop , where anyone in the community can come shop for a discounted bike . We call it Trips for Kids Re-Cyclery . All of the bikes and bike gear are donated . It provides 60 % of what we need to run our programs . And it is 100 % an environmental program . We follow the three 'Rs ' very rigorously : reduce , reuse and then recycle ! CNN : Trips For Kids has grown well beyond San Francisco . Why do you think this model works so well ? Price : It 's easy to use the bike to introduce kids to the environment because the bike is universally loved by children . The bike allows us to introduce them to a healthy lifestyle and good work habits . ( It 's ) a tool to impart these life lessons . Right now there are 90 chapters , literally around the world , that are repeating our experiences . They all do bike rides and then some of them , as they get more developed like we did , also start their own Earn-a-Bike programs or their own bike thrift shops to support themselves . CNN : Did you ever imagine your simple idea would have such an impact ? Price : I wear my Trips For Kids T-shirt wherever I go . I went into the bank one day here in Marin County , and there was a young girl who was the teller . She looked at my T-shirt , and she said , `` Wow -- you 're with Trips For Kids ? That was the best experience I 've ever had . I will never forget it . '' I do n't know how many stories there are like that , but it 's planting that seed . I just love every minute of it . Seeing the results of what we were accomplishing just had me stick with it . Since I started the notion , I have n't given up and hope to continue forever . Want to get involved ? Check out the Trips For Kids website at www.tripsforkids.org and see how to help .
For three decades , Marilyn Price has helped at-risk kids use bikes to experience nature . Her nonprofit , Trips for Kids , has more than 15,000 chapters worldwide , serving 90 children a year .