Geoff: In just over a week, Ukraine will mark four years since Russia's full-scale invasion began.

And now, in the depths of a frigid winter, under constant bombardment, and amid near-constant power blackouts, it may seem there is little space for art, or joy.

Especially for children.

Amna: But in the eastern city of kharkiv, there's a small corner, a half-century old, where children can learn the grace, discipline -- and yes, joy -- of theater.

Special correspondent jack Hewson takes us there.

For our arts and culture series, canvas.

Reporter: For 50 years, there a theater where children can come to play and perform together.

Rehearsals look like they always have.

Although everything around them has changed.

Since the Russian invasion, practice takes place under the constant threat of bombardment, predominantly for drones.

For 17-year-old Maria, the theater has become more.

>> At the beginning of the war, all my friends left and I had nothing todo.

I was scared to stay home alone.

I found out there was a children's theater inkharkiv.

I did not know about it at all.

I came and saw there were a lot of children here.

They were all having fun playing.

I knew if anything happened, that would save me because there was a shelter here.

Reporter: Teenagers rehearse alongside adult learning discipline, trust, and how to hold their nerve in a city under attack.

When Russia invaded, the nation scrambled to defend its borders.

For the director, it's about resilience, thriving, not just surviving.

>> We understand that first and foremost now is the front.

The army and everything related to it.

But I believe in a second place, should be art and theater and so on.

That should also be what we are fighting for.

Not only the fight for our freedom, but then what we do about our identity, about our culture.

Reporter: The performances shown here from the theater archived footage lend a greater weight for audiences strained by the emotional toll of war.

They bring moments of lightness, reflection, and simple escapism.

>> Many people tell us that at your performances, we cried out our pain and it becomes easier for us to live.

Someone says that at your performances, we forget that there is a war going on around S. And for this hour or two, it is important to get our minds off things.

Reporter: Suddenly we hear the sound of a drone overhead.

>> I need to get the children down urgently.

You also go down to the shelter now.

Let's go.

Everyone to the shelter now.

This second.

This second.

Quickly.

Reporter: Anton does not hesitate.

Everyone must go down underground as soon as possible.

All these kids have just had to come downstairs because a drone with heard overhead in the middle of an interview.

This is pretty much a routine occurrence.

They are on their phones.

It's normality for them.

But it's insane that they have to deal with this multiple times a week, multiple times a day.

This is normal life for children.

But as normal as this has become, harrowing individual stories are quickly revealed.

He's just 15.

>> A rocket flew over our house recently and then a rocket hit the house next door.

Reporter: You are very young to be experiencing things like this.

It's crazy.

How does it affect you?

>> It's so crazy.

It is not good.

No.

Reporter: Childhood here is lived under constant threat.

Yet, this has arguably been never more important.

The theater plays its most vital role yet.

> Now visiting the theater, they mentally survive.

But time will pass and paradoxically, I'm sure these memories will be some of their appiest.

How during the war they played Christmas plays for the whole city in this bunker.

We are very alive here in kharkiv.

This is the message to the world.

Reporter: As the error rates continue, displacement has become one of the few places where happy childhood memories can still be made.

For the pbs news hour, I'm jack Hewson in kharkiv, Ukraine.