Transcript for Syrian Refugees' Harrowing Journey Across Europe to Freedom
As president Obama pledges to help european countries shoulder the burden of the worsening refugee crisis, my "Nightline" coanchor Dan Harris there is with some of his most opt his stick travelers. Young, social media savvy, and with only desperation back home they welcome the uncertainty of the future. Tonight, their story. Reporter: It's the middle of the night and we're with a group of several hundred scared refugees. Moving en masse quickly, quietly, through farmland. It is pitch black. Trying to sneak across is border into Hungary. This is the largest mass migration in the history of Europe since world war ii. This is the front lines of it. As they move through the night, there are stops and starts. Everybody's very nervous. There are rumors flying about thieves in the bushes or cops up ahead. Everybody's very jumpy. They have good reason to be anxious. They've seen all the videos of Hungarian police clashing with refugees. They've also seen this now-infamous clip of the Hungarian camera woman tripping a refugee carrying his child in his arms. We have come to the Hungarian border following 11 young Syrian refugees whose journey from a war zone to a new life we've been tracking for days now. Are you nervous about approaching the Hungary border? Of course we're nervous. Because at this point we don't know how we are going to deal with it. Reporter: The unofficial leader is Ali, a normally jovial 21-year-old who tonight is on edge. My friends like telling me you must hide between the trees at night. If you are going to cross the Hungarian border, you are going to use it at night. Reporter: All of the refugees on the road tonight are tense. No photos, no Fote else to. Reporter: As they switch buses near the border, a fight breaks out. Ali struggles to keep his group together, pulling his friends up through the panicked mob. But as everyone is dropped off near the border, the group calms down and coalesces. And after a tense, confusing trek often in near total darkness, they make it to the border. It is just the latest harrowing step on a life-changing odyssey for these 11 young Syrians who I love Bruno Mars. Bruno Mars? Yeah. Reporter: She says she had an idyllic life in Syria until the war. We were terrified. We were threatened. My dad was threatened and my uncles got threatened. You cannot have your children if you don't give us money. Reporter: Driven by desperation and hope, these 11 Syrians are joining the human highway of refugees. Hundreds of thousands of people fleeing violence and terror in places like Syria and Iraq, making the 2,500-mile trip through Turkey over to Greece up through southern Europe and on to either Germany or Belgium. In order to get there, they first have to make the perilous passage from Turkey to Greece by water. They pay a smuggler $1,200 apiece to board a little boat that will take them to the island of lesbos. People have died making this journey. We were there when other refugees, including very young children, came ashore. These people, families, have just risked their lives, everything they own, everybody they love, to cross this narrow strait to arrive here in Greece. Refugees are often jubilant when they arrive safely in Greece. But like Ali and his crew they are quickly hit with hard reality. A sweltering 25-mile walk to the port for a ferry over to the Greek mainland. It's they:00 in the afternoon and we meet up with the group at a local cafe in Athens as they wait for a bus that will take them north. We're scared if they are going to open the roads or not. We don't have any choices. Hello. Reporter: Rawa is more optimistic. It will be a good journey. Reporter: They board the bus for the seven-hour journey to the border of Macedonia. Ali reflects on all that he's leaving behind, including his parents and his siblings. My heart is broken. I lost a lot of my friends. I'm going to miss my Syria. I'm going to miss my home. I'm going to miss my cars. I'm going to miss also my bed. Reporter: The next morning they cross from Greece into Macedonia. And that is where we lose them. Their cell phones aren't working. And we can't locate them at the camps. We go north to the Serbian border hoping to find 11 proverbial needles in a haystack of humanity. Seemingly out of nowhere, they spot our producer Jackie. Jackie! How is your trip? So now we are going to take the paper and we are going to Belgrade. Reporter: They board another bus for Belgrade, their last stop before that most unwelcoming of borders, Hungary it's been 13 long days since they left Turkey and everybody's now worried about this next leg. I heard a lot of people saying different things. Like the police will kill you, and you must escape from them. But I'm going to go see. Reporter: En route, Ali is glued to social media. His is a thoroughly modern migration. There's like a lot of we've been following for more than two weeks. Ali, where are you from? I'm from Syria. Hello. Reporter: We first meet Ali and his groupthe Turkish city of izmir on August 28th. He andriends areot N what U miyot pighurect when you think of refugees. They're from was who lost near the horrif,ic grinding war broke out in Syria four years ago. You'd just be killed? Yeah, any time. R start over in belgm.iu also in the group, Ali's niece Reading, and American music. Bruno mars.blican presidential candidate Carly fiorina, are raising security concerns. I mean, we are having to be very careful about who we let enter this country from these war-torn regions to ensure that terrorists are not coming here. I'm going to tell you song. Muslims, they are not terrorists. We are not terrorists. Reporter: Just hours ago, Ali and his friends got off a train and walked to the Austrian border. Now we arrive, huh? Reporter: They're finally safe now and feeling both reflective -- So was it worth it? It was worth it. Reporter: And also a little giddy. Asking us before we leave them to mark the moment together. You have a selfie stick? You traveled with a selfie stick? Reporter: For "Nightline," this is Dan Harris on the Austria border. Our thanks to Dan for that report.
This transcript has been automatically generated and may not be 100% accurate.