Earth Day’s 45th anniversary could be the most exciting year in environmental history. The year in which economic growth and sustainability join hands. It’s our turn to lead. So our world leaders can follow by example.
The first one was held on April 22, 1970 in America.
An estimated 20 million people took part in rallies across the US for the first Earth Day.
It is credited as the beginning of the modern environmental movement.
The event was founded by former US senator Gaylord Nelson, after seeing the 1969 massive oil spill in Santa Barbara, California.
Today the Earth Day Network includes 22,000 organizations in 192 countries, according to the website.
Earth Day has it's own flag which, perhaps unsurprisingly, features a picture of the Earth on it.
As well as Earth Day, you can celebrate Earth Week and Earth Month.
Hollywood star Leonardo DiCaprio hosted Earth Day 2000, with many other musicians, actors and performers taking part over the years.
There is an Earth Day anthem, performed to the tune of Beethoven's Ode to Joy but with lyrics about protecting the planet.