The Dakota Access Pipeline protests reached a violent peak yesterday as activists and police clashed at the Sacred Stone Camp in North Dakota. Native American tribes, predominantly the Sioux, and demonstrators have banded together in the last few months to protest a 1,200-mile pipeline that would transport crude oil from North Dakota to Illinois [3].

On Thursday, police attempted to remove protesters from their campsite on the land owned by Energy Transfer Partners, the company responsible for the pipeline, and arrested 141 people [4], according to NBC. The above video shows the military-style assault police launched on the activists. Authorities also deployed tear gas and fired bean bag rounds on protesters.

While protesters have been battling the completion of the pipeline, their demonstrations have just recently made national headlines. It's a complex issue, but here's the gist.

1. Native Americans contend the pipeline threatens their drinking water.

The pipeline crosses the Standing Rock Sioux tribe's main source of water under the Missouri River and they claim it will gravely limit their access to clean water. While the pipeline does not traverse the tribe of close to 10,000 people's land [5], it does encroach on their ability to live. Energy Transfer Partners and the builders of the pipeline stated they have factored the tribe's water into construction and implemented measures to prevent any leaks. The Sioux counter their argument with the fact that The Pipeline and Hazardous Materials Administration has counted close to 3,300 gas line leaks since 2010.

Another point of contention involves the land itself. Although the property is privately owned, the Sioux claim the pipeline crosses an ancient tribal burial ground [6].

2. Climate change activists also oppose the pipeline.

Climate change activists have joined the fight against the pipeline because they assert it continues American reliance on oil and perpetuates global warming. There's also the issue of clean drinking water, which is ostensibly another environmental issue. Estimates from Energy Transfer Partners say the gas line will transport 470,000 barrels of crude oil a day or about 374 million gallons of gas a day [7]. Activists warn that the pipeline is a step backwards from the push for more renewable energy.

3. President Obama tried to halt construction on the project.

Even President Obama has come to the defense of the Native American protesters; "You're making your voices heard," he said while addressing the tribal leaders [8]. Unfortunately, a temporary federal block on the construction was overturned by a court and the project proceeded. [9]

Many celebrities have also joined the fight. Susan Sarandon has appeared at rallies and Shailene Woodley was recently arrested during a protest [10]. After protesters were removed Thursday, construction swiftly continued [11] on the site where the violent clashes had transpired only hours before.