For thousands of years, long before there was such a thing as a science of chemistry, people were fascinated by plants, because they knew that plants contained substances that could affect people. Coffee will keep you awake. Tobacco contains something that will calm your nerves. Foxglove contains an extract that'll affect your heart.
Nature is impersonal, awe-inspiring, elegant, eternal. It's geometrically perfect. It's tiny and gigantic. You can travel far to be in a beautiful natural setting, or you can observe it in your backyard - or, in my case, in the trees lining New York City sidewalks, or in the clouds above skyscrapers.