Nearly all of the major milestones in U.S. and global environmental legislation have been enacted since the 1960s. Key policies and international agreements have been established for air and water quality, for plant and animal life, to heal the ozone layer, and to combat anthropogenic climate change. At the same time, a number of major environmental disasters—some with global reach—have left their imprint on our Earth and on our collective consciousness. Learn about the international efforts and grassroots activism that have changed some of the ways that we interact with our precious planet for the better, and take an honest look at just how far human stewardship still needs to advance.