 Complete the following phrase:  In 1992, Rio hosted the Earth Summit, a United Nations conference to fight environmental degradation. Twenty years later, in 2012, the city hosted another conference on sustainable development, named United Nations Conference on Sustainable Development. The city hosted the World Youth Day in 2013, the second World Youth Day in South America and first in Brazil. In the sports field, Rio de Janeiro was the host of the 2007 Pan American Games and the 