Adults tend to think of kids as "future citizens" -- their ideas and opinions will matter someday, just not today. But kids make up a quarter of the population, so shouldn't they have a say in what the world they'll inherit will look like? Urban planner Mara Mintzer shares what happened when she and her team asked kids to help design a park in Boulder, Colorado -- and how it revealed an important blind spot in how we construct the built environment. "If we aren't including children in our planning, who else aren't we including?" Mintzer asks. Check out more TED Talks: www.ted.com The TED Talks channel features the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes (or less). Look for talks on Technology, Entertainment and Design -- plus science, business, global issues, the arts and more. Follow TED on Twitter: www.twitter.com/TEDTalks Like TED on Facebook: www.facebook.com/TED Subscribe to our channel: www.youtube.com/TED