Seoul

South Koreas capital city has its weaknesses, according to YouthfulCities; it ranked 25th out of 25 major cities studied for its safety and mental health infrastructure among youths, for example. But while Seoul finishes last in one category, it finishes first in another. Seoul is, by YouthfulCities measure, the best city in the world for environmental stability. That means Seouls quality of water, recycling system, carbon emissions per capita and public transit participation is among the tops in the world.