The correct answer is Rio de Janerio in the year 1992 with a major outcome as 'Agenda 21'.The United Nations Conference on Environment and Development (UNCED), also known as the 'Earth Summit', was held in Rio de Janeiro, Brazil, from 3-14 June 1992.This global conference was held on the occasion of the 20th anniversary of the first Human Environment Conference in Stockholm, Sweden, in 1972. It had participants from 179 countries.The primary objective of the Rio Earth Summit' was to produce a broad agenda and a new blueprint for international action on environmental and development issues.One of the major results of the UNCED Conference was Agenda 21, a daring program of action calling for new strategies to invest in the future to achieve overall sustainable development in the 21st century.Additional Information The 'Earth Summit' had many great achievements such as:? the Rio Declaration and its 27 universal principles,the United Nations Framework Convention on Climate Change (UNFCCC),the Convention on Biological Diversity; and the Declaration on the principles of forest management.The 'Earth Summit' also led to the creation of the Commission on Sustainable Development.