At the Kurukshetra site, the team is digging through the Earth's layers of history, moving back to the early days of Khmer power in Southeast Asia.

-Each time we change level, usually it's 10 by 10 centimeter, we take another level.

Any artifacts within the layers could be minute.

-They know perfectly what to do, and they know perfectly what to look, what to take out, what is good and what is wrong, what is not necessary to keep, because they are working with me since 2009.

Mon -- She work with me since 30 years.

She's able to find one millimeter by one millimeter gold leaf.

[ Chuckles ] Incredible.

I don't know how she do.

[ Laughs ] She's very good.

Several layers have now been removed, exposing the earth to light and air for the first time in hundreds of years.

But have they dug deep enough to find anything from the pre-Angkorian period?

It's up to Christine's experienced eye.

Spraying the exposed dry, dusty surface with water will reveal any color variations.

These variations allow the archaeologists to identify sections in the wall that are called cultural layers.

-Here is different than here.

And they have found evidence of human habitation.

The discover of the cultural layer associated with human occupation of the site is a milestone for the team.

The search for any historical artifacts left behind now intensifies.

♪♪ After painstakingly combing through layer after layer of earth at the dig site, finally, a breakthrough.

The top of a pot is revealed.