Indigenous men wearing feathers and face paint play soccer at the summit on June 18.

The U.N. sustainable development conference plans to mark the 20th anniversary of the landmark Rio Earth Summit in 1992, which paved the way for the Kyoto Protocol in 1997. Despite the Kyoto Protocol and several other attempts to enact global environmental resolutions, world leaders are stilling struggling to break a deadlock between maintaining a shaky global economy and conserving the environment.

On June 20, the day the U.N. member countries' representatives fly into Rio de Janeiro, more than 50,000 protesters are expected to rally to bring attention to the decline of the global environment and the many failed attempts by international leaders to create a global solution.

A protester demonstrates against the controversial Belo Monte Dam project on June 18 at the summit.

Once completed, the Belo Monte Dam will be the third-largest hydroelectric dam in the world. Land surrounding the Xingu River in the state of Para will be inundated with water, washing out the homes of indigenous people and other residents.