The WHO Healthy Cities Program has been around since the mid-1980s and but is not as well known in the United States as it perhaps should be. The program is focused on “health development through a process of political commitment, institutional change, capacity-building, partnership-based planning and innovative projects” (http://www.euro.who.int/en/what-we-do/health-topics/environment-and-health/urban-health/activities/healthy-cities). Healthy city activities typically focus on fostering collaborations and partnerships to promote health with a refreshing mix of interventions—policies, programs, and plans. Activities that won Healthy Cities Awards in recent years include schools that promote urban health, injury and violence prevention activities, best practices in public toilets, and healthy urban transportation (http://www.alliance-healthycities.com/htmls/awards/index_awards.html).
It’s hard to find exactly how many cities participate but the WHO European office claims that over 1,400 European cities take part in 30 national networks. As the network is global, presumably the overall numbers are much larger. An Alliance for Healthy Cities brings some of these cities together: http://www.alliance-healthycities.com/htmls/about/index_about.html
The WHO European office has a useful healthy cities checklist that shows the wide range of topics of interest to the program from ecosystem health and public participation to diversity and economic vitality. You can read the whole list at http://www.euro.who.int/en/what-we-do/health-topics/environment-and-health/urban-health/activities/healthy-cities/who-european-healthy-cities-network/what-is-a-healthy-city/healthy-city-checklist.