Brief journey through the origins of acceptance of environmental problems starting with Carson´s Silent Spring (1962) followed by Meadows´ Limits to Growth, the 1972 Stockholm UN Conference on Human Environment and Our Common Future (1987) is given. The Earth Summit in Rio de Janeiro in 1992 and its tangible results in particular Agenda 21 gave a huge impetus to the process. Several important events and processes that followed are singled out. Among them: the 1997 UN Special session leading to the World Summit on Sustainable Development (Johannesburg 2002), setting the Millennium Development Goals in 2000, Millennium Ecosystem Assessment project, economic growth debate, and finally the idea of the planetary boundaries (Rockström et al., 2009). The preparatory process of the Rio + 20 Summit and its main topics (Green Economy in the Context of Sustainable Development and Poverty Eradication, Institutional Framework for Sustainable Development) are briefly analyzed.