On Sunday , April 22nd , people all over the world take time out to appreciate the earth that we all share .It's Earth Day , a special day to learn about our planet and how to take care of it . On Earth Day , some people listen to speeches about the environment . Others help clean up their offices or save water and electricity at home .Your parents may even decide to take a day off from driving their cars . The idea for Earth Day came from a U.S. Senator  . He was worried about pollution and the health of plants and animals . And the idea quickly caught on   . In 1970 , the first Earth Day was celebrated . More than 20 million people in cities all over the U.S. took part in it .Since then, Earth Day has been used to educate people about their roles in taking care of our planet . Now , Earth Day has become a worldwide celebration. In 1990, two hundred million people from 140 countries took part in clean-ups , tree planting and other environmental events on  Earth Day . Why has Earth Day become a worldwide celebration ? Because   _  .
Earth Day is on Sundays . we can sing songs on Earth Day there are so many people on Earth Day Earth Day can teach people how to take care of our planet