1945.

Disaster strikes.

The Empire State Building, a B 25 bomber with three crewmen on board, is on a routine transport flight from an Army base in Massachusetts.

It's flying over Manhattan, headed for Newark Airport just across the city.

The weather is relatively bad.

Visibility is poor.

There's fog across Manhattan.

What happens next?

Has no warning.

Traveling at over 200 miles an hour, the bomber flies straight at the Empire State Building.

It tears a 250 square foot hole in the 79th floor, carving a path of destruction, starting fires and snapping elevator cables.

One engine ripped through the entire building and breaks through the opposite wall.

The other engine tumbles down an elevator shaft, falling 1000 feet to the sub basement.

How does the Empire State Building survived this catastrophic accident?

Engineer Adrian Brugger explores this engineering mystery.

The bomber pierces through the facade.

It's an immense impact, like getting punched by a sledgehammer.

The B 25 Mitchell bomber is a formidable machine.

It weighs up to £35,000 and flies at nearly 300 miles per hour.

It strikes the north wall with an immense amount of energy.

How is it that people inside the buildings survived this disaster?

Steel beams make up the skeleton of the Empire State Building.

Adrian wants to test what force of impact they can withstand.

What you see here is a beam like you would find in the floor, Joyce or the floor beams off the Empire State Building and it would hold up the floors.

What we will see is how much Dr.

Till it e how much ability this steel has to actually deformed before it breaks.

Adrian applies three tons of force to the steel beam.

So now we are pushing on the beam still, and you can see that it's deflecting very heavily.

Something moved a little.

We're okay.

We can keep going.

As Adrian increases the weight load to 3.9 tons, the steel beam is still holding strong.

You could see this is absolutely amazing.

The beam is completely deformed in the middle, but it's still holding almost four tons of spring energy.

It looks like it failed, but it's actually still doing its work.

This steel has an incredible duct ill ity.

It can bend in half before it snaps.

A photo of the impact the B 25 makes on the building proves the incredible strength of the beams.

Here you can see these beams look very much like what we have here.

Their mangled, twisted, but they're not broken, and that's important.

They're not fractured, so they stayed in place.

And that's key.

The steel beams are bent, not broken.

The structure survives the main force of the initial impact.

Many escape.

Others are rescued by first responders.

14 people die in the tragic accident, but there is a miraculous survival story.

Astonishingly, the structure saved someone's life.

20 year old Betty Lou Oliver is an elevator operator.

She's blasted out of her elevator car on the 80th floor.

When the plane hits, onlookers hurry her into another car to get her to safety.

But as the doors close, the cable snaps and the car instantly drops As Betty Lou's car picks up speed.

The emergency brakes failed, but trapped air compresses in the shaft, slowing her fall and at the bottom of the severed cable forms a coil that cushions the impact.

Miraculously, Betty Lou's survives falling 1000 feet.

The Empire State building survived the plane crash, too.

But the moment of impact causes another potentially lethal risk to the structure and life inside.

Plane's Fuel ignites disastrously thes Exclusive motion pictures show the Empire State Building burning like a great smoky torch with flames bursting from the windows.

Fire and skyscrapers can be a deadly combination, but how does the building survive?

Adrian wants to find out how the Empire State Building steel skeleton stands up to the flames and intense heat to save the people inside.

Charming.

What I What we're Doing here is a simulation of what you would expect to happen in, for example, my department fire due to an airplane crash.

He hates the steel to find its breaking point.

Go, go more.

There you go.

That's it.

As the steel is heated, a machine pulls from both ends with increasing force.

Steel melts at 2500 degrees Fahrenheit, but just a fraction of that temperature is enough to seriously weaken the metal there.

It is actually about 420 degrees Celsius.

The fire from the exploding bomber will quickly rage to double this temperature.

Integrity of the Empire State Building steel skeleton will easily fail with the heat of a fire, it's vital the flames are put out before the skeleton fails and the building crashes.