Monday was set to be the first day of a landmark youth climate trial against the federal government over climate change, three years after the lawsuit was first filed.

But last week, the U.S. Supreme Court ordered a temporary stay as it considers a last-ditch attempt by the Trump administration to throw out the case from proceeding to trial.

In response, the 21 youth plaintiffs of Juliana v. United States, their attorneys and thousands of supporters rallied around the nation on Sunday and Monday to demand that the kids have their day in court.

More than 90 scheduled events were organized across 41 states, with key rallies in San Francisco, New York City, Boston, Portland, Washington, DC, Seattle, Colorado Springs and St. Paul.

The central rally was held Monday on the steps of the Wayne Morse Federal Courthouse in Eugene, Oregon, where the trial was supposed to take place.

A "huge spirited" crowd of 1,500 people—including 500 students who walked out of local high schools and the University of Oregon—braved occasional rains to attend the event, according to organizers.

350 Eugene director Patty Hine, Oregon State Senator James Manning, the youth plaintiffs and their attorneys gave speeches.

"The power of the people is more powerful than the people in power," 18-year-old plaintiff and hip-hop artist Xiuhtezcatl Martinez rapped in a stirring speech at the rally. "This is a movement founded in love."

The historic lawsuit was initiated by a group of teenagers and young adults against the U.S. government. They claim the government violated their constitutional rights to life, liberty and property by enacting policies that encourage climate change. The lawsuit was filed during the Obama administration and has survived multiple attempts by both administrations to halt the case. That was until Brett Kavanaugh was appointed to the Supreme Court.

"Our constitutional democracy allows us to protect our liberty without declaring independence from our government, so long as those who govern assent to review by our courts and let the facts be told," Julia Olson, executive director and chief legal counsel of Our Children's Trust and co-counsel for the youth plaintiffs, said in a press release. "These young people deserve that chance to present their case against those who govern and let the light fall where it may."

Kiran Oommen, a 21-year-old plaintiff, added in the press release, "On Monday, we rally for our right as American citizens to a fair trial. No matter how much the federal government might try to deny us that right, we will have our day in court. "

Watch here for a Facebook Live of the Oregon rally.