STANDING ROCK, SD -- When you check in on Facebook, most of the time you want to show where you are and not where you're not.
That's not the case in the Dakotas.
Hundreds of thousands of people are checking into the Standing Rock Indian Reservation even if they're thousands of miles away in real life. Construction of the Dakota Access Pipeline is happening in North and South Dakota.
The check-ins started with a Facebook post saying law enforcement were tracking protesters on social media and would have a more difficult time finding them if people around the country would check at the reservation. The local sheriff's office said they're not tracking protestors.
The Dakota Pipeline controversy is a $3.8 billion project that would transfer hundreds of thousands of barrels of oil a day from North Dakota to Illinois. Tribes have said construction is on their sacred land, and it could contaminate their major water source, the Missouri River.
People are now using the check-ins as a way to show their solidarity with the Native American tribes against the pipeline.
They're not the only ones, either. Celebrities, including Mark Ruffalo, the Rev. Jesse Jackson, and Shailene Woodley have been protesting on the land as well.