Earth Hour (earthhour.org) started in 2007 in Sydney, Australia when 2.2 million individuals and more than 2,000 businesses turned their lights off for one hour to take a stand against climate change. Only a year later and Earth Hour had become a global sustainability movement with more than 50 million people across 35 countries participating. The Tshirt / tree announcement reminds people of Earth Hour and the installation has appeared in major city parks around the world. This one is Dallas’ White Rock Lake, TX, USA. For Leo Burnett Inc.