Earth Day was founded over 50 years ago and now people all around the world are fighting for the planet [Video]

Millions of people around the world will pause on Monday, at least for a moment, to mark Earth Day. It’s an annual event founded by people who hoped to stir activism to clean up and preserve a planet that is now home to some 8 billion humans and assorted trillions of other organisms.

Here are answers to some common questions about Earth Day and how it came to be:

WHY DO WE CELEBRATE EARTH DAY?

Earth Day has its roots in growing concern over pollution in the 1960s, when author Rachel Carson’s 1962 book “Silent Spring,” about the pesticide DDT and its damaging effects on the food chain, hit bestseller lists and raised awareness about nature’s delicate balance.

HERE ARE SOME INTERESTING FACTS ABOUT EARTH DAY’S POPULARITY. WHO CREATED THE HOLIDAY?

But it was a senator from Wisconsin, Democrat Gaylord Nelson, who had the idea that would become Earth Day. Nelson had long been concerned about the environment when a massive offshore oil spill …