This organization works with people in third world countries to help develop a wheelchair that fits their particular needs, due to the rough terrain where they live. It recognizes the right of every person to have mobility - effective mobility. I think this photo of a young man in a specially designed wheelchair going down a very high curb shows very well why wheelchairs need to be customized to the environs.
In the photo at left, the wheelchair has a longer wheelbase which allows it to easily go down steps and curbs, unlike chairs currently used in the US. The front tires are wide and made of a softer material so they don't get "stuck" in holes and ruts. These special design features take into account the fact that there won't be curb cuts or paved areas. Because of where the foot rest is placed, even though the wheelbase is seven inches longer, the overall turning radius of this chair is lower than the average wheelchair.
If you go to their site, you can view a Quicktime video of these features. Or donate. Or read about how they are helping 45 third world countries mobilize people with disabilities.
And in the process, these wheelchair design features will ultimately benefit everyone.
Listen to some third world wheelchair users talk about their experiences in this video and how the wheelchairs allow them to continue to work.