Quartz: “In order to feel good, humans require interaction with nature. We have a genetically based affiliation with the natural world—a primal desire for the outdoors known as biophilia. This phenomenon describes our urge to connect with other life forms and manifests itself in our love of gardening and camping to owning pets, gifting flowers, and even selecting waterfall wallpapers for our smartphone backgrounds. The link between the environment and the health of the human mind is a growing subfield of psychology, and research shows clear evidence linking the physical world to the health of our mental world. For example, studies have found that exposure to nature helps reduce our stress levels, restores energy and mental focus, prevents depression, and aids healing of physical ailments, while too little exposure fosters anxiety, despair, numbness, and abstract grief. But many people don’t have access to these green, feel-good settings. More than half the world’s population currently lives in cities, where it can be hard to access nature in the quantities needed for optimal physical and psychological wellbeing. By 2050, the UN predicts that 70% of Earth’s population will live in urban areas. And with urbanization often comes more environmental destruction, which will only take us further away from the natural world…”