Sand Designs 'Out of this World' Special Edition to celebrate EARTH DAY 42nd Anniversary of Earth Day April 22, 2012 Forty one years after the first Earth Day, the world is in greater peril than ever. While climate change is the greatest challenge of our time, it also presents the greatest opportunity – an unprecedented opportunity to build a healthy, prosperous, clean energy economy now and for the future. Earth Day 2012 can be a turning point to advance climate policy, energy efficiency, renewable energy and green jobs. Earth Day Network is galvanizing millions who make personal commitments to sustainability. Earth Day 2012 is a pivotal opportunity for individuals, corporations and governments to join together and create a global green economy. Join the more than one billion people in 190 countries that are taking action for Earth Day. The thin line of Earth's atmosphere and the setting sun are featured in this image photographed by the crew of the International Space Station while space shuttle Atlantis on the STS-129 mission was docked with the station. Image Credit: NASA