When is Earth Day? Get ready to help your planet with our guide to the holiday.

For over 50 years, Earth Day has been celebrated across the country, and the globe, through the mobilization for environmental causes. While it may seem strange to think of a world without ecological awareness, there was once a time when Americans were even less unaware of their consumption's impacts on Earth.

Following the publication of "Silent Spring" by Rachel Carson in 1962, public concern began to grow for the environment and the links between pollution and health.

Though Earth Day is just one day, many take the initiative throughout the year to better our planet. To see how it started, here is the history of Earth Day and when it falls in 2024.

When is Earth Day?

Earth Day 2024 falls on Monday, April 22.

Why do we celebrate Earth Day?

Earth Day is celebrated in the U.S. on April 22 every year. While it is not a federally recognized holiday, many celebrate the day through environmental education, awareness and action.

Each Earth Day can "drive a year of energy, enthusiasm, and commitment to create a new plan of action for our planet," according to earthday.org.

Earth Day 2024 focuses on eliminating plastic usage "for the sake of human and planetary health." There is a goal to decrease plastic production by 60% by 2040 through shopping sustainably voting, participating in cleanups and practicing climate literacy.

When did Earth Day start?

The first Earth Day was celebrated in 1970 thanks to Sen. Gaylord Nelson of Wisconsin.

Nelson had been concerned about the environment for years and sought to educate people and raise public consciousness in the U.S. toward his cause, earthday.org reports. Along with Rep. Pete McCloskey, a California congressman, and Denis Hayes, an activist, they organized campus teach-ins on April 22.

Hayes helped grow their staff to promote events nationwide. The name "Earth Day" was then adopted, and media began to cover the cause, according to earthday.org.

That first Earth Day, 20 million Americans participated in various efforts to bring awareness to environmental causes, such as fighting pollution, oil spills and pesticides.

The first Earth Day sparked further conversation in politics, leading to the creation of the U.S. Environmental Protection Agency and the passage of first-of-their-kind environmental laws, such as the National Environmental Education Act and the Clean Air Act.

By 1990, Earth Day went global as 200 million people in 141 countries celebrated by calling attention to various environmental issues. Today, Earth Day is one of the largest secular observances in the world with over 1 billion people participating each year.

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This article originally appeared on USA TODAY: Earth Day 2024: What the holiday is, how to celebrate