In late 2014, with the war in Syria approaching its fourth year and Islamic State making gains in the north of the country, the exodus of Syrians intensified. At the same time, others were fleeing violence and poverty in countries such as Iraq, Afghanistan, Eritrea, Somalia, Niger and Kosovo.

Vast numbers of Syrian refugees had been gathering in border-town camps in neighboring Turkey, Lebanon and Jordan since 2011. By 2015, with the camps full to bursting and residents often unable to find work or educate their children, more and more people decided to seek asylum further afield.

In 2015 an estimated 1.5 million people made their way on foot from Greece towards western Europe via the "Balkan route". The Schengen Agreement, which allows passport-free travel within much of the EU, was called into question as refugees headed towards the wealthier European nations.

Tens of thousands of refugees were also attempting the perilous journey across the Mediterranean on overcrowded boats. In April 2015, 800 people of various nationalities drowned when a boat traveling from Libya capsized off the Italian coast. This was to be just one of many similar tragedies - by the end of the year, nearly 4,000 refugees were reported to have died attempting the crossing.

Countries along the EU's external border struggled to cope with the sheer number of arrivals. Fences were erected in Hungary, Slovenia, Macedonia and Austria. Asylum laws were tightened and several Schengen area countries introduced temporary border controls.

Critics of German Chancellor Angela Merkel's "open-door" refugee policy claimed it had made the situation worse by encouraging more people to embark on the dangerous journey to Europe. By September 2016, Germany had also introduced temporary checks on its border with Austria.

In early 2016, the EU and Turkey signed an agreement under which refugees arriving in Greece could be sent back to Turkey. The deal has been criticized by human rights groups and came under new strain following a vote by the European Parliament in November to freeze talks on Turkey's potential accession to the EU.

With anti-immigration sentiment in Europe growing, governments are still struggling to reach a consensus on how to handle the continuing refugee crisis. Attempts to introduce quotas for the distribution of refugees among EU member states have largely failed. Conflicts in the Middle East and elsewhere show no signs coming to an end, and the death toll from refugee sea crossings is on the rise.

Dragan (center), a Macedonian migrant, is hidden in the forests near the Serbian-Croatian border, as he tries to cross to central Europe with other migrants from Arab countries. Dragan, along with one Chinese migrant, is an oddity among the hundreds of Syrians and Afghans stranded in Šid, Serbia

Afghan asylum seekers on the roof of an old abandoned factory in Sid, which serves as a temporary abode, while away their time as they plot their next move to try and reach a western European country.

Migrants walk on the railway tracks which connect Serbia and Croatia near the northern village of Sid, Serbia. According to reports, two people were hit by a train after they had fallen asleep on the tracks.

More than 150 people are hidden in the so-called jungle — an area with dense bushes next to the train lines which connect Serbia and Croatia. Most have tried to cross to western Europe in different ways: either with the help of smugglers, alone or in groups, by jumping on trucks or hiding in freight train wagons.

Ibrahim from Afghanistan washes himself in a cold stream under a bridge near the Serbian village of Sid. Hundreds of refugees and migrants live in untenable conditions, without basic facilities and amenities.

"No Name Kitchen" is run by a small group of volunteers who distribute breakfast and provide help to refugees and migrants stranded on the Serbian-Croatian border. The authorities have largely abandoned the refugees.

Jadali, 22, from Afghanistan, had just returned to Sid following a failed attempt to reach western Europe. He was stuck in jail in Croatia for two days before being released by the authorities, who, as he claims, treated him roughly.

Two migrants cook dinner for those who gather in the abandoned factory during the evenings near the Serbian border village. Hundreds of asylum seekers face hunger, hardship, injuries and daily violence as they try to survive in the middle of nowhere.

A migrant walks towards a freight train. Moments later he will try to hide in an abandoned wagon in an attempt to cross the Croatian border and eventually reach another European country.

Those who can afford more expensive smuggling methods choose to pay taxis to take them across Croatia. The price for a ride is around €1,200 ($1,400).