NARRATOR: Egypt, birthplace of one

of the most enigmatic civilizations in history.

The pyramid tombs, and the Valley

of the Kings, the final resting places of powerful pharaohs.

Of the possible 63 tombs in the Valley,

there is one that outshines the rest

and has captured the world's imagination,

the tomb of Tutankhamun.

[dramatic music]

The Boy King was just 18 years old when he died,

but his priceless, golden treasures

have made him the most famous pharaoh of all time.

His funerary riches have been displayed all over the world,

but now they are all coming back to Egypt.

[dramatic music]

Cairo, in the shadows of the Great Pyramids.

Engineers are building a $1 billion

museum and research facility.

[suspenseful music]

The Grand Egyptian museum will house all Tutankhamun's

5,000 treasures in one place for the first time in 100 years.

[dramatic music]

One of the centerpieces of the museum

will be Tutankhamun's golden coffin.

[dramatic music]

Ahmed Abdrabou is leading the research

process to get it ready.

AHMED ABDRABOU: I must be very careful.

One of the bigger challenge for me

to be responsible for the restoration

of one of the masterpiece of the Tutankhamun collection.

NARRATOR: The coffin was one of many priceless treasures

found in Tutankhamun's tomb.

When Howard Carter's team opened the tomb in November 1922,

they discovered a wealth of treasures and gifts

the king would need in the afterlife, six

disassembled golden chariots, his throne, and provisions

of food and wine.

Concealed behind a false wall was

a stone sarcophagus protecting a gold plated coffin.

[stone scraping]

Inside it, two more coffins, the innermost made of solid gold

and covered in gemstones.

And inside that, the mummy of Tutankhamen,

wearing a magnificent death mask,

the most famous find in all of Egypt.

Ahmed needs to discover how the ancient artisans built

Tutankhamun's golden coffin.

The inside is made of wood, but the outside

is covered with a thin layer of precious gold.

AHMED ABDRABOU: Must to be very, very

careful, because I am working on one of the masterpiece.

[soft music playing]

NARRATOR: Under the lens, Ahmed discovers

an extraordinary secret.

AHMED ABDRABOU: The thickness of the gold leaf ranged

in between 14 and 18 micron.

NARRATOR: The ancient artisans could craft gold as thin

as shrink wrap, but to get a flawless finish,

they could not apply the gold directly

onto the uneven, chiseled wood.

Ahmed investigates closer, and finds a mystery layer

between the gold and the wood.

AHMED ABDRABOU: This is for the first time to see this.

NARRATOR: Ahmed finds a 3,300-year-old secret,

known only to the top craftsmen closest to the king.

AHMED ABDRABOU: This textile layer I think is linen.

[dramatic music]

NARRATOR: The ancient craftsmen used linen bandages

to smooth out the jagged wood and create a perfect finish

for the thin gold.

Almost 3,500 years later, we are still solving

the mysteries of Tutankhamun.

Ahmed is on the hunt for more clues.