Not sure if someone else posted about this already. From the LA Times:

Protesters said that those arrested in the confrontation had numbers written on their arms and were housed in what appeared to be dog kennels, without bedding or furniture. Others said advancing officers sprayed mace and pelted them with rubber bullets.

“It goes back to concentration camp days,” said Mekasi Camp-Horinek, a protest coordinator who said authorities wrote a number on his arm when he was housed in one of the mesh enclosures with his mother, Casey.”

Meanwhile, the State is very proud of their magnanimity:

Morton County Sheriff Kyle Kerchmeier said he was coordinating with Standing Rock officials to assist protesters in recovering teepees and other belongings, calling it a “a great example of communication, collaboration and cooperation.”  He added:  “I am very proud of our officers” who “responded with patience and professionalism and showed continuous restraint throughout the entire event.”

This happened in 2016 in America.