Speaking at a "No Kings" rally in Washington, D.C., Bill Nye, the former host of "Bill Nye the Science Guy," urged lawmakers to “stop the abuses of this petulant president [Trump] and his circle of sycophants,” declaring, “No thrones, no crowns, no kings."

Huge crowds mustered in cities for “No Kings” protests on Saturday in response to what organizers call overreach from President Donald Trump.

With chants, costumes and colorful signs, Washingtonians raised their voices against Trump's hard-line policies on immigration, the federal budget and more.

The demonstrations follow a wave of protests in June that organizers say drew more than 5 million people in cities across the country.

From New York City to California, millions of people are expected to join "No Kings" protests across the country on Saturday, Oct. 18.

The Pacific Northwest’s largest “No Kings” protest is set to take place in Seattle on Saturday, alongside several other rallies across western Washington.

At a “No Kings” protest in Washington, D.C., Bill Nye tells NBC News’ Melanie Zanona that federal cuts to science funding, especially around NASA, are “thoughtless.”