This Saturday could mark the largest anti-police violence protests the United States has seen since Michael Brown was killed in Ferguson this August.

Washington, D.C. and New York City will play host to the two largest demonstrations this weekend. In the nation's capital, the families of Eric Garner, Michael Brown, Akai Gurley, Tamir Rice and Trayvon Martin—all black men and boys recently killed by white law enforcement—will join Rev. Al Sharpton and several civil rights organizations in Freedom Plaza at 10:30 a.m. ET for an all-day event.

Though the Justice For All march will take place in Washington, D.C., it's led by the National Action Network, the New York City-based organization founded by Sharpton. NAN and other groups have organized buses to carry demonstrators to the capital early Saturday morning, and the group will be supported by the American Civil Liberties Union and the DC chapter of the NAACP. Turnout is expected to be in the thousands, and should shut down major streets such as Pennsylvania Avenue.

New York City's Millions March grew out of a loose affiliation of unaffiliated protest organizers and several organizations such as Black Lives Matter, The Rockaway Youth Task Force, the New York Civil Liberties Union and others. The event will start in Washington Square Park at 2 p.m. ET, and around 42,000 people have said they will attend on the march's Facebook page as of this writing.

In this Dec. 5 photo, protesters rallying against a grand jury's decision not to indict the police officer involved in the death of Eric Garner stage a "die-in" at the Apple Store on Fifth Avenue, in New York. Image: Jason DeCrow/Associated Press

The march has its own website, which lists several "demands" organizers want to spotlight.

They want Daniel Pantaleo—the officer who put Eric Garner in a chokehold, causing his death—to be indicted. They also want an independent prosecutor's office that would oversee incidents of alleged police abuse, and a New York state agency that oversees police departments, among other items.

Protests in the capital have so far been peaceful, and although demonstrations in New York City had a few ugly moments after a grand jury did not indict Pantaleo on Dec. 3, they have been significantly calmer than anything that took place in Ferguson after Brown's death.

Demonstrations in New York City and around the country have flared up almost nonstop since the non-indictment decision. They've included protests outside Barclays Center in Brooklyn during a visit by Prince William and Kate Middleton, a series of somewhat tense demonstrations in Berkeley, California, and many more.

Trash on fire in the middle of Telegraph between 21st and 22nd #berkeleyprotests pic.twitter.com/3hWvca6hX5 — Patrick Kulp (@PatrickKulp) December 10, 2014

For protesters, the goal is to take all these moments of rage and turn them into lasting change.