■ The UN Conference on the Human Environment in Stockholm in 1972 brought 113 nations together. The 1972 Stockholm Declaration was signed at the conference, enshrining the “no harm” principle as the basis for international environmental law.
■ The conference adopted 5 June as UN World Environment Day, and the date has been observed ever since. The conference also established the United Nations Environment Programme (UNEP), which coordinates UN environmental efforts from its headquarters in Nairobi, Kenya.
■ On 5 June 1972, 200 police officers with horses and dogs clashed with demonstrators who tried to stop delegates from attending the conference opening ceremony. This was the first time a riot barrier had been used in Stockholm. The police operation involved 1,623 officers and 281 vehicles.