Ukraine's Refugee Crisis—in Five Heartbreaking Videos

More than 1.7 million people have fled Ukraine in what the United Nations has called the fastest-growing refugee crisis since World War II.

In the 13 days since Russia invaded its neighbor, people have left their homes with what they can carry, desperately seeking a safe haven in Poland and other neighboring countries.

As the number of refugees soars, videos have captured heartbreaking moments—a crying child walking across the border; a father's tearful goodbye; and a little girl's singing lifting spirits in a bomb shelter—that illustrate the devastating toll of the war so far.

Here are just five of them:

Weeping Boy Walks to Poland

One video captured a boy weeping as he crossed the border into Medyka, Poland.

It wasn't clear if the child was alone, but he didn't appear to have anyone with him when the clip was filmed.

"Excruciating," CNN correspondent Josh Campbell said in a tweet with the clip that has amassed more than 2 million views.

Chaos at Kyiv Train Station

Tatiena Stanieva shared multiple videos that captured the chaos as thousands of people desperately tried to flee the Ukrainian capital.

Stanieva wrote that she spent three hours in a traffic jam before she arrived at Kyiv-Pasazhyrskyi station.

"I have never seen such a concentration of fear, panic and horror anywhere," Stanieva wrote.

Singing in a Bomb Shelter

A Ukrainian girl's moving rendition of "Let It Go" from Disney's Frozen captured the hearts of viewers.

Amelia sang a Ukrainian version of the song to a group of families sheltering from danger in Kyiv, according to Marta Smekhova, who posted the clip on Facebook.

"Everyone put their business aside and listened to a song by this girl who was just beaming light," she wrote.

A Father's Goodbye

As women and children flee Ukraine while men stay behind to fight, many families have been separated from their loved ones.

One emotional video captured a man saying a tearful goodbye to his wife and daughter.

It's not clear where exactly the clip was filmed, but the man is seen putting a winter hat on his daughter's head before they both cry profusely. He then embraces his wife and daughter shortly before they leave on a bus.

Music Outside a Station

A pianist was captured playing "What a Wonderful World" as refugees milled outside a station in eastern Ukraine.

The clip was shared on Twitter by Reuters' special correspondent Andrew Marshall, where it has amassed more than 3 million views.

"Outside Lviv station, which is thronging with exhausted refugees fleeing war in eastern Ukraine, an accomplished pianist is playing "What a Wonderful World." It's hauntingly beautiful," Marshall wrote.