Painters and poets throughout the millennia have explored the aesthetic beauty of trees in great detail, and in the past few centuries, humans have become intimately aware of how trees form the foundation of many natural systems. Recently, the United Nations Environment Programme (UNEP) launched their major worldwide tree planting campaign, "Plant for the Planet: Billion Tree Campaign". One major component of their outreach efforts is this very fine website, which includes sections such as "Facts and Figures", "Trees and Humanity", and of course, "How to Plant a Tree". On the site, visitors also have the option to pledge their support for the project in a variety of ways. The "Facts and Figures" section is also helpful, as it contains answers to a number of basic questions such as "Where are forests found?" and some more specific information on the importance of this project.