Last Day of Passover
Many Jewish communities in the United States mark the last day of Passover as the end of a Jewish holiday that celebrates the deliverance of Jewish people from slavery in Egypt. Passover is also known as Pesah, Pesach, or the Feast of Unleavened Bread.
Oklahoma Day, which is annually held on April 22, commemorates the date when the "Oklahoma Lands" area, which is now the state of Oklahoma, opened for European settlement.
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.