We evolved in natural surroundings. Today, we live stressed, harried lives in urban surroundings. This is an important reason why we suffer anxiety and depression.
The attached article shows that time spent walking in nature can relax us, with expected long term benefits.
Understanding this is important; personally, we can choose to bring nature into our lives and; socially, we can design our ways of life and our cities with nature.
Proof that exposure to nature can quiet the rumination of a worried mind.
Source: Nature Therapy