The proportion of the global population living in urban areas has risen from half in 2000 to 55 percent now, and is predicted to reach two-thirds by 2050. That means more people than ever will be away from nature, which means people are missing the proven health and wellbeing benefits that come from being in nature. Fortunately, crowded cities around the world are getting more creative in the ways they add greenery to urban areas. From tree-covered skyscrapers to green roofs, here’s how cities are becoming more natural.