The business of moving migrants is booming in the ancient city of Agadez, Niger, as human trafficking replaces tourism at the gateway to the Sahara.

Agadez has been a main departure point across the Sahara since the 15th century, and now it’s a jumping-off point for Africans desperate to leave the continent.

More than half of all West African migrants on their way to Lampedusa, Italy, pass through Agadez — up to 80,000 in 2014 — and the International Organization for Migration expects that number to double in 2015, according to a report in NYTimes.

Those migrants bring money that is transforming this far-flung corner of the global economy. The previous heyday of this remote Saharan trading post was as a medieval stopover for caravans carrying salt to Mediterranean markets, Wall Street Journal reports.

Once in Agadez, the’ll spend an estimated $100 million this year on trips to Libya alone, officials say.

This gateway to the Sahara is booming again, this time as a vital hub in the largest wave of migrants since World War II.

The picturesque narrow alleys of Agadez’s mud-­brick Old City have been all but abandoned by tourists because of terrorist and kidnapping threats in recent years, NYTimes reports. But new construction is reaching beyond the airport that once delivered the tourists — thanks, in part, to the migrant business, say international officials.

“These are people who used to work in the tourism industry,” said Giuseppe LoPrete, head of the International Organization for Migration office in Niger, in a WSJ report. “They don’t see themselves as smugglers. For them, it’s a business.”

In Niger, most people live on less than $2 a day, but the streets of Agadez are jammed with Toyota pickups driven in from Libya, motorcycles, and sedans, Wall Street Journal reports. New villas made with cement have solar panels and satellite dishes on the roofs, crowding out the mud-brick homes. Camels have become rare.

“We help the poor reach places of opportunity,” said Idriss Mohammad, who runs a trafficking business in Agadez. “That’s the new tourism.”

In five years, Mohammad said he has made enough money to buy a five-bedroom home and a convenience store. Now, he’s buying new vehicles, he told the Wall Street Journal.

As many as 2,000 migrants leave Agadez every week, the last major stop before reaching Libya, 620 miles away across the Sahara Desert, NYTimes reports. The government of Niger has begun cracking down on the traffic in the face of outcry in Europe over illegal migration, but business is still booming.

The government’s new anti-­trafficking laws have done little to end the lucrative migrant trade in Agadez, despite recent arrests, according to NYTimes. The city’s permanent population is around 90,000.

A “connections man” — English words are used as the job title for human traffickers in this former French colonial outpost — can earn $50 or more per migrant, and an entire economy has sprung up around them.

Migrants hide from authorities behind high iron gates in what locals call “ghettos,” waiting for the next convoy of pickup trucks to take them across the desert.

“It’s bringing our city to life,” said Abdourahamane Moussa, deputy secretary-general for the regional government, according to WallStreetJournal. “Migrants are buying things, consuming our goods, animating our economy. People here are benefiting.…How can we stop it?”

Many people — “the drivers, the fixers, the landlords” — are earning an income off migrants, Deputy Mayor Ahmed Koussa told NYTimes.

Without more decisive action, “the Ivorians and Gambians will invade Europe,” said another deputy mayor, Aboubacar Ajoual.

In Agadez, 14 banks and hundreds of money-transfer agencies serve the city that had no ATMs 10 years ago. Amadou Massoï’s cash-wiring operation consists of a cellphone, notebook and wooden bench. His daily turnover: $16,443.94 on a recent day; $17,911.05 the next; $19,718.90 the day after that, according to WSJ.

Niger is one of the world’s poorest countries but in Agadez,  the market stalls are full of fresh produce, and only the nation’s capital, Niamey, has more ATMs — all signs of the trafficking economy, according to NYTimes.