"One hundred years from now ... they're going to hear those songs. They're going to hear that memory of what happened here at this camp."

Outside Standing Rock Sioux Reservation, North Dakota (CNN) -- A prophecy warned that this time would come. A black snake would arrive to destroy the Earth. It is now slithering across this land, disturbing what's sacred and gearing up to poison the water.

For the Native Americans who gather in camps near the Standing Rock Sioux Reservation, this snake has a name.

They call it the Dakota Access Pipeline.

In solidarity with allies who've come from all different places and backgrounds , they are determined to stop this $3.7 billion project that would transport 470,000 barrels of crude oil a day through four states.

Corporate greed and the potential for an environmental disaster -- should the pipeline leak or break -- are two arguments against it. But the more complicated issue challenging Western sensibilities is about threats to sacred land.

What's at stake, and what does it even mean to be sacred?

The 'grandmother'

Faith Spotted Eagle

Seated in a camping chair, Faith Spotted Eagle, 68, pulls a blanket around her to ward off the cold. Though she lives on the Yankton Sioux Reservation of South Dakota, Spotted Eagle has traveled to these pipeline opposition camps to help women define their roles here.

Part of her mission as a "grandmother" -- the term used to describe wise female elders -- is to bring people back to what's sacred.

As Spotted Eagle speaks, the smell of campfires hangs in the air and the sounds of chainsaws fade away. When the sun disappears behind the clouds, the temperature plummets. The landscape is brown, the wind biting and the arrival of winter palpable.

A small airplane, presumably monitoring the camp, circles from time to time. Men behind her prop up cedar poles.

They're constructing a new tipi for a baby she's come here to welcome.

A baby girl with a symbolic name

Just three weeks before, in the large army-style tent, a baby girl was born. She signifies hope in an ominous time, and her name reflects that.

She is Mni Wiconi -- Water is Life.

JUST WATCHED Meet Mni Wiconi, or Water is Life Replay More Videos ... MUST WATCH Meet Mni Wiconi, or Water is Life 00:33

It's a name or phrase that long predates this baby's birth. It appears on T-shirts, vehicles and signs all over the camps. It is painted on purple tie-dyed fabric that hangs beneath a large dreamcatcher near a food tent across the uneven dirt road where the sacred fire, lit on day one, is guarded and still burns.

Every tribe, Spotted Eagle says, has a story about water being threatened. For this reason, people here say they're not protesters; they are "water protectors."

A view of a protest camp near Cannon Ball, North Dakota.

It's not just sacred land at stake now -- it's the water as well. The Missouri River and all the tributaries that flow into it, including the Cannonball River that runs by the camps, are sacred.

Water is the "first medicine;" it sustains us in our mother's womb, Spotted Eagle says. It's used in ceremonies to heal people. The steam it gives off in a sweat lodge, for example, purifies. Water can clean a spirit when it's bleeding. It can calm a person and restore balance.

Its power goes even deeper, though. Water, she says, also has memory. When people speak or sing to it during a ceremony, it is believed that the water holds on to what it hears and can later share what it learns.

So when a group of women gathers on the river's bank next to the crowded main camp and they hold up tobacco offerings while singing prayers, the water is listening.

"One hundred years from now, somebody's going to go down along the Cannonball River and they're going to hear those stories," Spotted Eagle says. "They're going to hear those songs. They're going to hear that memory of what happened here at this camp."

Echoes with power

Native American protestors and supporters walk along land being prepared for the Dakota Access Pipeline.

Oftentimes burial grounds are the sacred sites that are threatened or destroyed. But understanding what these grounds look like, what desecration means, requires wisdom most of us don't have.

Spotted Eagle gives an example: What if the Great Sioux Nation decided to build a project through Arlington Cemetery?

"The point would be taken that you don't disturb people that have been put to rest," she says.

That's easy enough to get.

But it turns out, leaving burial sites alone is about more than simple respect. Protection prayers -- those that ensure the deceased will not be disturbed on their "walk to the spirit world" -- are recited over relatives who are buried. If spirits linger, like they might in the case of violent deaths, and are then interrupted, "They're not going to be able to find their way. They'll still roam on this land," Spotted Eagle says.

"Archaeologists come in who are taught from a colonial structure, and they have the audacity to interpret how our people were buried. How would they even know?" Faith Spotted Eagle

Then consider this: Who's to say where ancestors are buried? Certainly not Western archaeologists, Spotted Eagle says. She believes they are no more qualified to make these determinations than she would be if she set out to survey a Hutterite cemetery.

"Archaeologists come in who are taught from a colonial structure, and they have the audacity to interpret how our people were buried," she says. "How would they even know?"

Over the course of thousands of years, can they identify the correct stone placements or the specific sorts of vegetation? What's sacred cannot be confirmed through their eyes, she says.

Youths ride horses at an oil pipeline protest encampment near Cannon Ball, North Dakota.

She says 38 miles of the Dakota Access Pipeline cuts through territory that still belongs to Native Americans, based on a 1851 treaty signed at Fort Laramie in Wyoming.

She still holds out hope that through legal channels her people will prevail in shutting down this pipeline.

'They're coming home'

Two children walk together in oil pipeline protest encampment near Cannon Ball, North Dakota.

Just as water holds memories, so does the earth.

In this same place in 1713, there was a Sun Dance -- a tribal ceremony featuring dancers, songs and the beating of a traditional drum. If you listen carefully between 3 a.m. and 4 a.m., Spotted Eagle says, you "can hear eagle whistles [used in ceremonies]. You can hear people kind of mumbling and talking and praying."

Those echoes from the land have a power that draws people, allowing them to connect with their roots.

And you can see that across the camp.

Flags representing supporters and ideas line the road and dot the landscape. Ones for the Leech Lake Band of Ojibwe and the Tulalip tribes fly next to an RV bearing the sign, "Muslims Standing with Standing Rock Sioux." There's a gay pride rainbow flag, a POW/MIA flag and an American flag hung upside down.

Flags of Native American tribes from across the US and Canada line the entrance of the camp.

Some are living in an old school bus painted with blues, greens and purples. There are high-end tents, campers and tipis, and failed structures with tarps blowing in the wind. One open tent offers winter jackets hanging on metal racks. Another advertises with its bright yellow sign: "Free feminine hygiene & baby" products.

A man with a microphone announces a training in "direct action principles," the rules to live by in camp that include being "peaceful and prayerful."

An upside-down American flag seen inside the camp in North Dakota.

Many of the Native Americans who have come here in recent months, Spotted Eagle says, are arriving from urban areas around the country.

Whether they know it or not, they likely carry an ancestral suffering they've inherited from generations past, says Spotted Eagle, who also works as a PTSD therapist serving veterans and tribes.

Protestors march to a construction site for the Dakota Access Pipeline.

It's important for people to face and know who they are.

By building relationships on this sacred land at this crucial time, "they're coming home," experiencing ceremonies like many haven't before, Spotted Eagle says.

They signal a "rebirth of a nation."

Like an umbilical cord

The new women's lodge has been completed for the baby girl.

Like all tipis, this one has 13 poles -- the 13th being the woman's pole. Attached to it is the canvas, which wraps around like a skirt, enfolding the tipi "just like the woman enfolds her family," Spotted Eagle says.

The rope hanging down inside anchors the tipi to Mother Earth, much like an umbilical cord.

Spotted Eagle helps pass on sacred understanding, but she's also a longtime activist. She railed against the Vietnam War, helped develop the first Native women's shelter and was on the front line with other grandmothers in the battle against the Keystone XL Pipeline.

The people behind the Dakota Access Pipeline, the capitalists who she says cannot seem to get enough, make her think of one of the gifts the new baby, Water is Life, will receive.

After birth, baby girls are given beaded turtles. Inside, tucked away and sewn in, they keep their "belly buttons," meaning their fallen-off umbilical cord stumps.

It's a custom that reminds Native Americans of their connections, and perhaps it explains what is wrong with the forces behind the pipeline, Spotted Eagle says.

"When people don't know where their belly buttons are, they don't know where they belong," she says. "So they keep digging all their lives."

Water is Life shouldn't have that problem. It will be hard to forget the sacred place from where she came.