Five things you didn't know about Earth Day

1. One billion people across the world will get involved with Earth Day this year
2. The celebration has its own flag that features a picture of the Earth taken from the Apollo 17 spacecraft on its way to the Moon
3. 20 million people participated in the first ever Earth Day in 1970
4. No one knows where the name or date for the day came from as the organisers can't remember
5. In 2008 Disney launched Disneynature, a channel dedicated to environmental documentaries, in celebration of Earth Day
6.