First Earth Day
Source: earthday.org
The first-ever Earth Day was held in the US almost exactly 50 years ago on April 22, 1970.
The organisers wanted to raise awareness of concerns such as pollution and toxic waste and were inspired by the anti-war movement led by students at the time, according to its website. Earth Day has now become a global event ever since 1990, when 200 million people in 141 countries joined forces to bring it to the world stage.