Twenty years after Brazil hosted the first international summit on sustainable development, the rising-star South American nation is playing host to the United Nation's conference once again. The so-called Rio+20 summit, which began on June 20, is the culmination of literally decades of environmental policy, projects, and new thinking about the way that humans exist on the planet. "It is...in everyone's interest that all countries, not just some or even most of them, advance towards sustainable development," summit Secretary General Sha Zukang reminded audiences in his opening remarks on Wednesday. "This is one planet—with one common future."