World Trade Center glows orange for the March for Our Lives rallies

The lights came from One World Trade Center's 408-foot spire, which Gov. Andrew Cuomo ordered to be lit orange in honor of the marches. Cuomo marched earlier Saturday in New York.

"Today is the day we unite to say the NRA is not going to win," Cuomo said. "The people of the United States are going to win the day and common sense is going to win the day.

"The spirit of youth and activism seen and heard on the streets of our cities and throughout our nation today will carry forward --- first tonight in the lights of New York's highest tower and tomorrow in the change that must follow. The youth of this movement are angry at Washington and they're angry at the lack of leadership, and they should be. And they're saying if you won't lead, we will lead."

So why orange? It dates to at least 2013, when 15-year-old Hadiya Pendleton was shot and killed in Chicago. Hadiya was an honor student who was killed in a case of mistaken identity -- a week after she performed at one of the events surrounding President Obama's second inauguration.

Her friends picked the color orange to honor her and to call for gun reform because it's the color hunters wear to avoid being shot by other hunters.

"Orange is what hunters wear in the woods to protect themselves and others from harm," the organization Wear Orange explains. "Orange is a bright, bold color that demands to be seen. Orange expresses our collective hope as a nation -- a hope for a future free from gun violence."

Students and New York's tallest tower haven't been the only ones wearing orange. Celebrities at the Oscars this year also wore orange pins.