As "megacities" grow in Africa and Asia, assuring residents long-term access to clean water may require a multidisciplinary approach.
With climate change comes more flooding. As cities confront the risks and potential damages, trees could become even more important.
Research shows that building collisions take a staggering annual toll on North America's bird population.
Once polluted and abandoned, back alleys have sprouted into flourishing rain gardens.
Urban apiculture is a booming trend. But many metropolitan beekeepers also believe that bees fare better in cities than they do in the countryside.