Five charts that help explain Europe’s migrant crisis

The Syrian civil war has caused the worst refugee crisis since World War II: More than 3 million Syrians have fled abroad, with nearly 200,000 seeking asylum in the European Union.

Most end up in Italy, but fewer than 1 percent stay there, opting instead to continue north along an “invisible railroad” over Europe’s porous borders to migrant-friendly countries in Northern Europe, such as Germany and Sweden.

It’s a complex geopolitical and legal maze as families hopscotch from country to country, evading authorities until they reach their chosen destination. The lucky ones find help along the way from locals; others suffer harassment and abuse, or fall victim to European traffickers seeking to profit from human misery.

For more on the “Invisible Railroad”, tune in to the premiere of Compass with Sheila MacVicar on Sunday, May 10, at 9:30 p.m. ET/6:30 PT on Al Jazeera America.

For most migrants, the saga begins years before setting foot on European soil. The Syrian refugee crisis is part of a larger wave of Middle Eastern and African migration across the Mediterranean. Last year set a new record for illegal border crossings, according to the European Union’s border agency Frontex, and this year’s numbers suggest the surge is far from over.

Not everyone makes it to shore. Last month, a ship carrying an estimated 850 migrants capsized and sank in the Mediterranean Sea, drowning all but a couple dozen passengers. The U.N. called it the deadliest incident in the Mediterranean ever recorded. Lately, disasters like this have become all too frequent: Just the week before, 400 sea-crossing migrants died in a similar disaster.

Since 1988, about 20,000 people have died trying to reach Europe, half of them in the last five years. According to the International Organization for Migration, 2014 was the worst on record for migrant deaths, and this year is on track to be even deadlier.

The surge in deaths underscores a call from migrant activists and humanitarian non-profit groups for more search-and-rescue missions such as Italy’s Mare Nostrum, which saved at least 100,000 lives last year before being discontinued in late 2014 and replaced with a less-effective European operation. Meanwhile, many politicians have stressed a need to go after the human traffickers that exploit desperate migrants.

Nearly everyone who reaches Italy sets sail from Libya, where political upheaval and lawlessness have allowed smugglers to operate with no consequences. Libya was long a destination for refugees escaping war and poverty, but its recent descent into chaos has encouraged more people to make the risky trip across Mediterranean and seek safety in Europe. Factoring in the fairly short distance to Lampedusa, Italy's southernmost island, Libya has developed a reputation among Middle Eastern and African refugees for being the primary pipeline into Europe.

The high demand for passage across the Mediterranean has created brutal conditions aboard boats. Migrants pay smugglers exorbitant prices for a place on vessels that are often overcrowded. Some are so called ‘ghost ships,’ pushed off the coast of Libya towards Italy with no one steering. Along the way, migrants risk abuse, robbery, and death due to violence or exhaustion. Some are simply thrown overboard to drown.

Most who make the journey are refugees seeking asylum. Despite the dangers, they say the risks are far lower than that of staying in Libya or returning to their countries. Last year, Syrians were the biggest single group of cross-Mediterranean migrants, closely followed by Eritreans, who are fleeing forced military conscription and persecution. Political and economic turmoil in Afghanistan has also been a driving factor for many to seek better lives in the EU.

The large number of Syrians still displaced in the Middle East and North Africa suggests that this migration pattern will likely remain.

At least 90,000 Syrians fled to Egypt, where they’ve borne the brunt of a sudden wave of xenophobia that followed President Mohammed Morsi’s removal. Fearing harassment and deportation, many were forced to leave. More than 1 million are in Lebanon, where they face discrimination and unemployment in an unstable political situation. Other Middle Eastern countries have struggled to provide jobs and basic services for the huge numbers of refugees, making mainland Europe an increasingly attractive option. Inside Europe, the prolonged economic crisis and the rise of anti-immigration sentiment have narrowed the list of countries willing or able to take them in.

Meanwhile, the U.S. and U.K. have both pledged to provide asylum to legitimate refugees, but with difficult asylum application procedures, few refugees have reached either country.