Nearly a million of those have applied for asylum in Europe, according to the U.N. refugee agency.
Among those are Somar and his younger sisters, Salsabil and Lubna. Their trip to Germany was documented by Italian photographer Alessio Mamo
, who met up with the family in September.
"During this journey, which lasted about a month and a half, I was able to 'hide' between them and document the trip from various stages -- sleeping in camps, traveling in trains and buses, eluding several controls and checkpoints," Mamo wrote in an email.
The family traveled through Turkey, Greece, Macedonia, Serbia, Croatia, Slovenia and Austria before reaching their destination.
"The trip was sometimes easy and sometimes hard," Mamo said. "The difficulties started in Kas, a small village in Turkey from where they started their journey by boat to Greece. At the beginning, Somar thought to buy a small boat and try to cross the sea to Kastellorizo. Then he realized that was too hard, so he decided to pay a smuggler for around 1,000 euros each (about $1,100 U.S.)."
The trip from Macedonia to Serbia was also difficult, Mamo recalled. After a long train ride, they crossed the border with a 5-kilometer (3.1-mile) walk at sunrise.
But Mamo also set out to show a "less miserable view" of the refugee experience. His photos show the family swimming in picturesque waters and taking selfies with friends in Greece. Some of the friends went to college with Salsabil; others, they met along the way.
Somar, 28, was an engineering student who left Syria three years ago and moved to Jordan. Salsabil, 21, and Lubna, 14, were living in the Syrian capital of Damascus until September, when they linked up with their brother at Istanbul's airport.
"For a long time, I had in my mind the idea to follow a refugee family," Mamo said. "The opportunity came when I met Somar for the first time in Jordan. A common friend introduced him to me. He told me the idea to reach his brother in Germany. So immediately I asked to follow them during their journey and do a photographic project about it. Somar did not hesitate one moment: He immediately said yes."
Somar's brother Mousab lives in Schwabisch, Germany, with a wife and son. After reuniting with Mousab in Germany, Somar and his sisters now live in Mosbach, a small city between Stuttgart and Frankfurt. They are going through the registration process, Mamo said. But there is still a long way to go.
"They are not worry-free because they always think about their parents in Damascus," Mamo said. "And they are going to German school because they know that if they want a future in Germany, they need to learn German."