- Hi, I'm Ken Burns.

We're going through a difficult time right now.

The uncertainty can be overwhelming, as we're worrying about our family, friends and community.

Amid all this, one encouraging thing that's starting to happen is a collective mobilization, both on the national and global levels.

We're seeing retired medical professionals volunteering to serve, neighbors helping one another, distilleries producing hand sanitizer, and engineers inventing creative solutions with 3D printing.

It reminds me of examples of collective resolve from major catastrophes in our past.

And my mind keeps going back to this particular moment from World War II, when the entire American automotive industry was converted to produce wartime equipment.

We tried to capture it in this clip from our film THE ROOSEVELTS.

(lively jazz music) - [Narrator] Idle factories were soon back in business.

Nearly all manufacturing was converted to the war effort.

In 1941, more than three million cars had been manufactured in the United States.

Only 139 more were made during the entire war.

Instead, Chrysler made fuselages.

General Motors made airplane engines, guns, trucks and tanks.

And at its vast Willow Run plant in Ypsilanti, Michigan, 67 acres of assembly lines under a single roof that one observer called "the Grand Canyon of the mechanized world," the Ford Motor Company performed something like a miracle 24 hours a day.

The average Ford car had some 15,000 parts.

The B-24 Liberator long-range bomber had one 1,550,000 parts.

One came off the line at Willow Run every 63 minutes.

(lively jazz music) - Amazing.

Isn't that amazing?

The Grand Canyon.

Virtually the entire industry switched its production to what the country needed most.

Our current crisis won't be solved easily, and there will be more dark days ahead.

But what brings me hope for the future is looking at the past and finding some comfort in those moments when we were able to come together.

Please stay safe, and take care of yourself and your family and those with needs greater than your own.