A massive wave of migration is crashing through North Africa, but there is only one major gateway to Europe — and it’s through Libya.

Coming from the south, migrants flee the vestiges of wars that have left entire nations in ruin. From the east, they escape a life of indefinite military servitude and violent conflict. From the west, they evade destitution and governments that arbitrarily jail whomever they please.

Some arrive by choice, others by force. But Libya is the purgatory where most migrants prepare to face the deadliest stretch of the Mediterranean Sea.

The costs of the journey — both human and monetary — match a steep sum of desperation and demand.

The conundrum Libya poses for policymakers is that the root of its wave of migration does not come from a single source. Like a flood of tributaries streaming to the mouth of a river, migrants are fleeing en masse from at least a dozen different countries.

Shutting off the flow would mean addressing the needs of migrants spanning half of an entire continent.

The country’s 1,100-mile coastline has effectively become an open border without government forces to monitor who comes and who goes. Smugglers have filled the void, willing to tightly pack hundreds of migrants at a time into flimsy vessels and shuttle them to Italy.

Migrant crossings through the central Mediterranean jumped by more than four-fold after 2013. The International Organization for Migration estimates that nearly 182,000 migrants from Libya have landed in Italy since the start of last year, exacerbating a massive refugee crisis already spilling out of Syria and other parts of the Middle East.

For years, broad regions of sub-Saharan Africa have been swallowed by squalor and extreme poverty, crushed under the rule of oppressive governments or caught in the crosshairs of deadly groups that thrive on terror.

But suddenly, technology made the world much smaller and dreams more concrete. Facebook feeds were now flooded with pictures of friends and family who had made it to Europe, projecting the notion that a dramatically improved lifestyle was easily within reach. Remittance packages from loved ones abroad proved that higher wages were not merely a myth. Connections to smugglers selling safe passage to a new life were all of a sudden just a phone call away.

Gaddafi once proudly served as protector to his country’s maritime border, promising that, for a sizable compensation from Europe, makeshift loads of human cargo would not suddenly arrive in search of refuge on Italian shores.

But in the time since Gaddafi’s fall from power and subsequent death in 2011, international attention on the flood of migration has grown, reflecting the level of desperation that fueled the crisis. Suddenly, it wasn’t just migrants arriving in Italy by the thousands — a disturbing number of corpses were also washing up on shore.

European authorities have tried to crack down on the practice, turning back the boats still out at sea. Many migrants are deported outright. But for every smuggler’s ship that is seized by authorities, a new, often rickety, version replaces it, launched at the peril of those onboard.

The journey will drag them through several layers of hell before their toes even touch the sea.

Of the entire African continent, Eritrea — the country that sends the highest number of migrants to Europe — is roughly equal in size to the state of Pennsylvania. Nearly 40,000 migrants fled Eritrea last year, escaping a government notorious for one of the worst human rights records in the world and for condemning citizens to lifetimes of mandatory military service.

But neighboring Somalia, another distressed country located along the eastern Horn of Africa, has its own migration push-factors at play, pinned to decades of armed conflict, now leading to the rise of al-Shabaab rebels throughout the region.

Referred to as “the backdoor to Europe,” the lines of migration link a diverse region. In a single leg of the journey, one might find a mix of Nigerians displaced by the militant insurgent group Boko Haram, Gambians escaping a brutal authoritarian government, or Senegalese existing on the brink of survival.

Five out of the six countries that border Libya have either been engulfed in war or are in the midst of violent unrest. In order to reach the ports that serve as the gateways to Europe, migrants first must spend months, even years, criss-crossing the Sahara or the countries still raw from violent armed conflicts.

The desert has turned into a massive hub for human smuggling, with migrants shuttled between refugee camps, stash houses, even tucked inside the hollowed-out center of a merchant’s lorry. Those who survive share horror stories of kidnappers who held them for ransom, waiting hours, days, or weeks until families back home or in Europe opened up their pocketbooks once again.

Migrants caught in the crossfire are often used as pawns in the power struggle. Thousands languish in overcrowded detention centers on any given day, and allegations of torture and unsanitary conditions have led to concerns of widespread human rights violations.

The country is a place of limbo as migrants face chaos and prepare for the next leg of their journey. Tenements dot the major ports of migration, filled with mostly African men in search of jobs to fund their travels.

For a time, Libya’s economy was largely propped up by the labor of foreign workers. The oil-rich nation was once a prosperous land of opportunity. But now, there’s not much by way of jobs. And with each new wave of migrants trucked into the coastal cities, opportunities diminish.