Monday is Earth Day 2019, and more than 1 billion people across the globe are expected to celebrate with environmentally friendly events. But what exactly is Earth Day? Here's what you need to know: >> Read more trending news 1. When did Earth Day start? The first Earth Day celebration took place 49 years ago, in 1970, after a devastating oil spill in America brought environmental issues to the forefront of public consciousness. According to the Environmental Protection Agency, 22 million people across the country came out in support of environmental reform. 'That day left a permanent impact on the politics of America,' Gaylord Nelson wrote in the April 1980 edition of the EPA Journal. 'It forcibly thrust the issue of environmental quality and resources conservation into the political dialogue of the nation. 'It showed political and opinion leadership of the country that the people cared, that they were ready for political action, that the politicians had better get ready, too. In short, Earth Day launched the environmental decade with a bang.' Since then, celebrations have only grown. This year, organizers estimate more than 1 billion people in 192 countries will participate in events the world over. The day is celebrated each year on April 22. 2. Is there a theme for Earth Day 2019? This year's Earth Day theme, 'Protect Our Species,' focuses on helping endangered and threatened species. 'The unprecedented global destruction and rapid reduction of plant and wildlife populations are directly linked to causes driven by human activity: climate change, deforestation, habitat loss, trafficking and poaching, unsustainable agriculture, pollution and pesticides to name a few. The impacts are far-reaching,' the Earth Day Network, which partners with tens of thousands of organizations in 192 countries to organize Earth Day events, said on its website. 'If we do not act now, extinction may be humanity’s most enduring legacy.' The organization's goals include educating the public 'about the accelerating rate of extinction of millions of species,' protecting species with 'major policy victories,' creating a 'global movement,' and urging people to take 'individual actions such as adopting [a] plant-based diet and stopping pesticide and herbicide use.' Read more here. 3. How are people celebrating? More than 3,000 community cleanups are scheduled in dozens of cities, including Miami, Seattle, New York, Los Angeles and Washington, D.C., the Earth Day Network reported. 'Plastic pollution and waste challenge every community, every day, and these cleanups offer a chance to make a real difference,' the organization's website said. Interested in volunteering? Learn more here. 4. What are businesses doing? Google marked Earth Day 2019 with an interactive doodle featuring facts about six 'awe-inspiring organisms' on our planet, including the wandering albatross, coastal redwood, Paedophryne amauensis (a tiny frog), Amazon water lily, coelacanth (a rare fish) and deep cave springtail. >> On Google.com: Click here to see the doodle and learn more about it. Apple also joined in on the celebrations, announcing on April 18 that it is 'quadrupling the number of locations U.S. customers can send their iPhone to be disassembled by Daisy, its recycling robot.' “Advanced recycling must become an important part of the electronics supply chain, and Apple is pioneering a new path to help push our industry forward,” Lisa Jackson, Apple’s vice president of Environment, Policy and Social Initiatives, said in a statement. “We work hard to design products that our customers can rely on for a long time. When it comes time to recycle them, we hope that the convenience and benefit of our programs will encourage everyone to bring in their old devices.” Meanwhile, the company unveiled its Earth Day Challenge, which 'encourages Apple Watch wearers to complete any workout of 30 minutes or more to earn a special Earth Day Award and stickers for Messages.' Apple Stores will have 'environmentally themed Today at Apple sessions' Monday, as well. Read more here. 5. How can I get involved? There are multiple ways to get into the Earth Day spirit, from participating in a local event to changing your bills from paper to paperless. Here are some suggestions from the Earth Day Network: Urge your local elected officials or businesses to make a substantial tree planting commitment by starting a letter-writing campaign or online petition. Lead a recycling drive to collect as much plastic, metal and glass as possible. Pick up trash at a local park or beach. Set up a screening of an environmentally themed movie. Consider supplementing the screening with a speaker who can lead a Q&A following the film.