home to the world's most iconic monuments,

the mighty pyramids of Giza.

The pyramids once housed the bodies of the pharaohs.

But though ancient Egyptian civilization lasted for nearly

3,000 years, its kings only built huge tombs

like these for a few centuries.

Egyptologists are still trying to piece

together why the pharaohs stopped

constructing giant pyramids.

For Egyptologist Chris Norton, the majesty

of the ancient structures makes the fact

that Egyptians gave up building them all the more incredible.

10 miles south of the legendary pyramids of Giza is Saqqara.

CHRIS NAUNTON: When we think about pyramids,

we tend to think of Giza, I think, and the Great Pyramid

of Khufu in particular.

But actually, this is where it all began.

NARRATOR: Chris has come to the birthplace of pyramid building

to search for clues to why Egyptians built giant pyramids

for less than 500 years.

Constructed a century before the iconic pyramids at Giza,

Egypt's first pyramid is a 200 foot tall mausoleum

of six huge limestone platforms carefully

engineered to spread the weight of rock and prevent collapse.

Deep inside is a giant shaft 26 feet wide and 82 feet deep.

At the bottom, the intended final resting place

of the Pharaoh Djoser.

CHRIS NAUNTON: Ultimately that's what it's all about.

That's where the body of a king is going to rest in eternity.

So you've gone to all this trouble

to create this incredible monument

around the body of that person.

It's pretty amazing.

NARRATOR: To house his mummy, huge chunks of granite

were slid down a passage into the shaft

and stacked, creating a giant sarcophagus

19 feet long and 11 feet high.

CHRIS NAUNTON: My god, these pieces are huge.

Wow, it's amazing.

NARRATOR: But this wasn't just a tomb

designed to secure the pharaoh's physical body for eternity.

Crucially, for success in the afterlife,

the pyramid ensured the king was remembered by the living.

Completed around 2,650 BC, it sparked

an architectural revolution.

Djoser's six tier giant wasn't just the first pyramid.

It was the world's first monumental structure

built in stone.

Over the next century, Egypt's kings develop the concept,

building monumental tombs all along the Nile's West Bank,

including the first geometrically true pyramid,

the Red Pyramid, and the misshapen

experiment, the Bent Pyramid.

Then a dynasty of pharaohs built the most iconic monuments

in Egypt, the pyramids of Giza.

But just a few short centuries after the Great Pyramid

of Khufu rose from the desert, a new era was on the horizon.