What is Earth Day and what has it achieved?
By Mark Poynting & Maddie Molloy
Every year, millions of people across the globe gather on Earth Day to celebrate the environmental movement.
The event began in 1970 in the United States, and is now marked around the world.
Earth Day is a global event which aims to highlight the importance of protecting the environment.
It takes place every year on 22 April.
It was set up in 1970 by Gaylord Nelson, a US senator and environmentalist, and Denis Hayes, a graduate student at Harvard University.
Both had growing concerns about environmental damage in the US, such as that caused by a large oil spill in 1969 in Santa Barbara, California.
They came up with Earth Day as a way to engage the public and push green issues to the national agenda.