12 powerful images from the Standing Rock protests

What started out as as a line of peaceful protests in defense of Standing Rock Sioux tribe's water supply has turned into the focal point of political conversation in recent months.

The Dakota Access Pipeline, a proposed $3.8 billion oil transmission line across North Dakota, South Dakota, Illinois and Iowa, was brought forth by Energy Transfer Partners. The company is reportedly preparing to tunnel under Lake Oahe, which the tribe fears will pollute local water supplies and foul its sacred tribal sites..

In late October, Senator Bernie Sanders rallied against the Dakota Access Pipeline and took to Twitter to defend the cause. 

Here are just some of the most powerful photos from the ongoing nationwide protests:

Protesters in Philadelphia demonstrate in solidarity with members of the Standing Rock Sioux tribe in North Dakota over the construction of the Dakota Access oil pipeline on Nov. 15.Matt Rourke/AP
Erin Wise of Cannon Ball, North Dakota, leads protest march from the Army Corps of Engineers headquarters to the White House. Chip Somodevilla/Getty Images
Activists gather in front of the White House during a rally against the Dakota Access Pipeline. Alex Wong/Getty Images
Holly Doll, an enrolled member of the Standing Rock Sioux tribe, holds a protest sign outside the state capitol building in Bismarck, North Dakota, on Oct. 29. John L. Mone/AP
Demonstrators chant as they gather in from of the White House in Washington on Sept.9.Jim Watson/Getty Images
Cousins Jessica and Michelle Decoteau, both enrolled members in the Turtle Mountain Band of Chippewa, don slogans opposing the Dakota Access Pipeline on Oct. 29.John L. Mone/AP
Sen. Bernie Sanders greets Jasilyn Charger, member of Cheyenne River Sioux Tribal Youth Council, after Charger spoke to a group of supporters of the Standing Rock Sioux Tribe. Jacquelyn Martin/AP
Omaka Nawicakincinji Mendoza, 7, holds a sign while on the shoulders of his father, Bill Mendoza at a White House rally.Jacquelyn Martin/AP
Hundreds of demonstrators block the entrance to the Army Corps of Engineers headquarters as they protest against the proposed Dakota Access Pipeline on Nov. 15.Chip Somodevilla/Getty Images
Protestors against the construction of the Dakota Access Pipeline block a highway near Cannon Ball, North Dakota, on Oct. 26.James MacPherson/AP
Juan Flores, a traditional Aztec dancer, looks on during a rally on Sept. 13 in San Diego, California.Sandy Huffaker/Getty Images
A demonstrator raises his fist next to a placard as they gather in front of the White House in Washington, on Sept. 13.Jim Watson/Getty Images