The Assassin (Sha ren zhe Tang Zhan)

In this episode...

This is one of the most structurally impressive

engineering projects in the world.

...An airport on course to be

the largest on the planet...

This airport is the benchmark for airport construction.

This is the most important thing I have ever done.

And the groundbreaking innovations from the past...

This is a wonderful piece of architecture,

a wonderful piece of engineering.

It's really a marvel.

It's almost a cathedral to good engineering.

...That made the impossible possible.

captions paid for by discovery communications

Beijing, China.

One of the biggest cities in the world.

Demand for air travel here is soaring.

But the city's only airport has reached its breaking point.

New York-based architect Wendy Fok

has traveled to Beijing to see how the designers

and engineers here are attempting the impossible.

The current airport is at capacity.

It was originally intended

for 76 million passengers each year,

but it's operating well above that.

Last year alone,

100 million people passed through its doors.

Problems for flight reliability,

passenger experience, airline operations.

Beijing is in real need of a solution.

With passenger numbers predicted to rise even further,

the pressure on the airport is only going to get worse.

So engineers in China

have come up with a groundbreaking solution.

This is the brand-new Beijing dashing international airport.

It's on track to become the biggest airport in the world

once construction is complete.

And Wendy is getting the chance to see it

before it opens to the public.

Wow, I cannot believe how high the ceilings are.

All of those dips and swirls are super amazing.

You could barely even see how the structure is done.

It's really well-designed.

Barely see any columns here.

It's really amazing what the engineers have done here.

Occupying more than 17 square miles,

dashing airport's site is 2/3 the size of Manhattan.

The spectacular star-shaped terminal

covers 7 1/2 million square feet.

With a massive roof constructed from over 57,000 tons of steel

equivalent to 500 steam engines.

By the time the entire project is fully completed,

it will include a record-breaking six runways

and could see 100 million travelers every year.

But with the old airport at crisis point,

constructing this massive terminal is a race against time.

Wendy is finding out more

from deputy engineering manager Gao Aiping.

So Mr. Gao saying

they need to build this entire terminal

in three years and nine months.

That is an incredibly short amount of time

to build an airport.

Quickly laying the groundwork for this complex mega structure

was the first step.

So Gao and his team came up with an innovative solution

to speed up construction.

So the engineers constructed a temporary railroad system

to the core of the building to bring the materials

to get distributed around the building

to move materials really quickly.

16 wireless, remote-controlled trains

transport up to 28 tons of construction materials,

making the build four times faster.

How many people are making this project possible?

Oh, wow, that's actually pretty amazing.

At peak times, there's about 20,000 people

working on this project.

And you can actually see there's a huge amount of people

just working on different parts

of the construction right now.

With this ample workforce, engineers hope

this entire terminal can be completed in record time.

But first, there are still major obstacles to overcome.

How do you move millions of passengers

through the airport efficiently?

How do you build the terminal's colossal

intricately curved roof?

And most importantly,

how do you protect the airport from devastating earthquakes?

I think this is one of the most structurally impressive

engineering projects in the world.

Before this astonishing structure can be built,

there's a crucial challenge with the design

that needs to be solved.

Getting to your gate at the airport

sometimes is an impossible feat.

You sometimes get lost.

You don't see the signage,

and sometimes, you're just rushing in general.

For a huge airport like this

to get over 72 million people through its gates,

it's going to be super difficult.

Designing the airport to guide passengers through it

is something that engineer Wang Qiang has to solve.

This is an incredibly difficult problem for engineers.

So how do you move people around the airport efficiently?

This is midtown Manhattan.

It's the heart of New York City,

the largest city in the United States,

and by virtue of being a place where everyone wants to be,

one of the busiest cities.

Architect Cara Michell is investigating

how her 19th century predecessors

dealt with the sudden increase in demand

for public transportation.

So it was an incredible challenge

for the early architects of New York City

to figure out how to get people onto and off of the island,

especially during a time of unprecedented population growth,

so figuring out a solution

for how to transport both regular commuters

and long-distance travelers on a daily basis

was really difficult.

A massive new transportation hub would need

to coordinate the smooth movement of people through it

on a scale that had never been attempted before.

Architects Whitney Warren and Charles Reed

took on the challenge of designing a new train terminal.

Their solution?

This is grand central terminal.

The largest railway station on the planet.

750,000 people pass through daily.

Warren and Reed came up with ingenious ways

to ensure passengers didn't get in each other's way.

First of all, you enter the main concourse,

and you immediately see this information center.

But you can also see the location of the tracks.

You understand immediately where you need to go.

You know, that is really accentuated by the fact

that there are no interior columns breaking up this space.

It's really an open plan.

No columns meant

a passenger's view of signs was not obstructed.

But there was still a major problem.

Stations usually had stairs,

which slowed people down and created bottlenecks.

So these ramps really represent

one of the major design innovations

in grand central terminal.

But one of the things they had to work on

was determining what the right gradient would be,

and they actually built a number of models

and tested them out to determine what the right slope is

for people carrying luggage

and even people of variety levels of fitness and ability

to make sure that it was just subtle enough

for people to feel comfortable,

but also the right slope to effectively

and quickly move people in and out.

So let's see.

It looks like we're getting something between

5 1/2 and 6 degrees of slope, which seems about right.

Grand central terminal was the first station

to use ramps on a large scale,

much more efficient than using stairs or even escalators today.

Another one of the many

innovations in grand central terminal

is the fact that the tracks are actually on two levels.

Typically, rail tracks are laid out in a row,

but with 43 platforms at grand central,

that's a long way to walk.

By splitting the tracks over two floors,

it's less distance for passengers to walk.

And there's another benefit.

So you have long-distance passengers

who need a little bit more time to get on the train,

have more baggage, on the upper level,

and then you have short-trip commuters on the lower level.

And another innovation is looping tracks.

So they're actually dropping passengers off on one platform

and then looping around

to board departing passengers on another platform.

Every piece of design and architecture

in grand central terminal

is really focused on getting people

moving more efficiently and more quickly through the station.

Grand central terminal is a world first.

Despite being built in 1913, it still works perfectly today.

So what Warren and Reed accomplished here

over 100 years ago truly revolutionized

the design of transportation hubs,

and it's quite a wonder to think

that designers of transportation hubs all over the world

are still looking to this space to understand

how to effectively move people around.

I mean, it's really a marvel and a monument,

almost a cathedral to good engineering.

Now, in China,

engineers are building upon