The answer is biophilia

In his article about the intuitive sense people have of the restorative power of natural environments, Alex Hutchinson asks, “The question is: Why?”

It’s easily explained through the phenomena known as biophilia, first hypothesized by the renowned Harvard biologist E.O. Wilson. The hypothesis provides an account for humans’ innate love of nature and other living systems through the lens of evolutionary psychology: essentially, since much of our evolutionary history was spent living within natural environments, we have a strong subconscious preference to be close to it. Considering the many benefits they provide for human wellbeing (not to mention many other environmental benefits), natural systems should be encouraged to be further integrated within the built environment.