Did you know this year marks the 53rd Earth Day? Celebrated globally in over 190 countries, Earth Day was first proposed by Gaylord Nelson, a Wisconsin senator, as a response to his concerns over the deterioration of the United States’ environment, including a 1969 oil spill in Santa Barbara, California. Drawing inspiration from student anti-war protests at the time, he wanted to combine the energy of the protests with an emerging public consciousness about air and water pollution. Inaugurated the following year on 22 April 1970, the first Earth Day was born. Want to test your knowledge? Check out Earth Day’s official website for quizzes on climate change, clean energy, and more.