[ Silence ]
>> I'm standing in one of the entrances
of the Rising Star Cave System.
This cave system is part of the Cradle
of Human Kind World Heritage Site in South Africa.
It's less than a kilometer away from the famous site
of Sterkfontein and even closer to Swartkrans.
Two sites that we're going to consider
in great detail in this course.
For the last 3 weeks here I've been part
of a remarkable expedition,
which has uncovered what may be the richest trove
of hominin fossil bones ever discovered in Southern Africa.
For 3 weeks we have been working to pull more
than a 1,000 numbered bone fragments out of this cave,
and they current represent more
than a dozen skeletal individuals.
This is truly a remarkable discovery.
This expedition is called The Rising Star Expedition.
The initial discovery of the chamber
in which the fossil hominins have been found was made
in early October of 2013.
Pedro Boshoff, who is an experienced geologist
and caver working with Lee Berger, Paleoanthropologist
at the University of the Witwatersrand
and National Geographic explorer in residence --
Pedro was searching around caves for deep caverns
that might contain traces of fossil bone.
In The Rising Star System he found an interesting slot
that he couldn't get into
and so he enlisted 2 other experiences cavers
with a unique ability to get into very narrow spaces;
Rick Hunter and Steve Tucker.
Those two cavers proceeded down through a very narrow slot.
A slot that ultimately was a 12-meter downward climb
and at it's narrowest points only 16 centimeters wide.
When Rick and Steve got to the bottom
of the slot they saw bones.
They came back to the site, they took photos of the bones,
they showed the photos to Lee and he immediately saw
that we were looking at an early hominin.
Well, Lee organized an expedition to come to this site.
The members of the expedition to go into the advanced chamber had
to have very special skills.
They had to be able to make it through that narrow slot
and they had to have advanced caving or climbing skills
to do it and they had to have archeological skills to be able
to do the work in the cavern; documenting, uncovering
and ultimately packing to come
out of the chamber the hominin bones.
He found 6 young women with the right combination of skills
and they became our advanced team down in the chamber.
The cavern lies more than 30 meters underground,
but it's a 200 meter traverse through he cave system
through a couple of very technical climbs and of course
down that very narrow squeeze to get to the advanced chamber.
Everything that goes into that chamber in terms of equipment
and supplies has to go in through that narrow slot.
And everything that comes out of that chamber has had
to be lifted out of that slot.
This is has been a very challenging expedition.
This expedition has been unique in terms
of the technology applied.
We have camera system in the cave for safety.
We have COM systems going back and forth not only
to the advanced chamber,
but also to safety points inside the cave.
As the archeologists work to excavate the bone
from a soft sediment, they rapidly discovered
that we weren't looking at a single hominin skeleton,
we were looking at many individuals,
and for 3 weeks we have been pulling bone out of that cavern.
It's amazing to me as a part of the expedition
that such incredible discoveries are still
out there waiting for us to find them.
That's really one of the messages of this expedition.
That by exploring systematically,
by sending people into places where people may have been going
for a long time, but have never noticed what's around them
when they get there,
we can still find remarkable evidence of our evolution.
We don't know yet what species of hominins we're looking at.
They're not modern humans.
We don't know how old they are.
We haven't yet been able to apply dating methods
to this cavern to find out when the hominin fossils got there.
What we know is that we're looking at a remarkable sample
that includes, at this time more than a dozen skeletons.
I've worked on a lot of hominin fossil sites
and there have been some remarkable samples
around the world.
But nothing quite matches this.
And one of the most exciting things for me
as a Paleoanthropologist is understanding that this part
of the world is not unique.
Every part of the world still has discoveries waiting
to be made.
As we develop this science, as we look more and more
at the aspects of our evolutionary history
that have been hidden to us in the past we're going to need
to reach out to use the techniques
that we're inventing here in other parts of the world,
in other fossil sites, in other contexts.
We're uncovering these fossil bones and sharing the process
of science as we do it.
Unique among paleoanthropological
expeditions, we've been live tweeting what's going
on in and out of the cave.
We've had blogs written by me, our other project scientists,
some of our experienced cavers and staff
from the National Geographic Society.
We've got videos out there
and those videos are getting into schools.
We've been doing Skypes with schools around the world.
We are sharing this as broadly as possible.
It is so exciting to be able to share this science
as it's happening, and so while I wish that I could share more
with you because I wish I knew the answers already,
I know that my journey as a scientist is still going on.
And so our journey together understanding human origins is
also going to continue evolving.