Hundreds and thousands of years ago, holidays and celebrations were defined by the time of year. Autumn was a time to celebrate the changing of the seasons, the bounty of the fall harvest, and the potential discomfort of a long, dark, and cold winter. Holidays noted pinnacle times and transitions. Spring brought with it a release from winter chill in exchange for brighter and longer days and the start of planting.

The 1970s saw the advent of a new holiday that helped solidify the environmental movement. The annual planetary celebration was dubbed Earth Day. Gaylord Nelson, a Democratic senator from Wisconsin, started the holiday. Growing up in northwestern Wisconsin, Nelson enjoyed exploring the outdoors, and as a senator, one of his speaking points was the environment.

Nelson strongly believed that the environment — and the impact people had on it — was not receiving the attention it deserved. He worked with President John F. Kennedy, who shared his belief, even doing a conservation tour in 1963. Still unable to get a foothold in the political movement, environmental concerns were perpetually relegated to the backseat as other pressing issues gained recognition.

During the summer of 1969, Nelson was speaking about conservation and witnessed the energy of antiwar-demonstration teach-ins. He knew then that if he could harness similar enthusiasm for the environment, his battle to protect the planet would be successful.

He organized a day of observance for environmental issues — April 22, 1970. In preparing for the event, the media and other politicians clamored to be involved, helping to make it a day like no other and striking the match that would fuel the environmental movement.

Today Earth Day is celebrated in a variety of ways, from community events and parades to political gatherings. Many use the day to promote environmental issues such as sustainable living and global climate change.

The Earth Day Network includes a list of celebrations and some great ideas for organizing an event.