<P> The United Nations Conference on Environment and Development (UNCED), also known as the Rio de Janeiro Earth Summit, Rio Summit, Rio Conference, and Earth Summit (Portuguese: ECO92), was a major United Nations conference held in Rio de Janeiro from 3 to 14 June 1992 . </P> <P> In 2012, the United Nations Conference on Sustainable Development was also held in Rio, and is also commonly called Rio + 20 or Rio Earth Summit 2012 . It was held from 13 to 22 June . </P> <P> 172 governments participated, with 116 sending their heads of state or government . Some 2,400 representatives of non-governmental organizations (NGOs) attended, with 17,000 people at the parallel NGO "Global Forum" (also called Forum Global), who had Consultative Status . </P>

When was the rio+20 summit in rio de janeiro held