Earth Day originally celebrated at Spring Equinox around March 20, is an annual day on which events are held worldwide to increase awareness and appreciation of the Earth's natural environment. The name and concept of Earth Day was pioneered by John McConnell in 1969 at a UNESCO Conference in San Francisco. He proposed March 21, 1970, the first day of spring in the northern hemisphere. This day of nature's equipoise was later sanctioned in a Proclamation signed by Secretary General U Thant at the United Nations. A month later a separate Earth Day was founded by United States Senator Gaylord Nelson as an environmental teach-in first held on April 22, 1970.