In 1807, the slave trade was ended in Great Britain. Twenty-six years later, the Slavery Abolition Act made human bondage itself illegal throughout the British Empire. In the United States, the ratification of the 13th Amendment in 1865 inserted a ban on slavery directly into the Constitution. The League of Nations in 1926 approved an international treaty “to secure the complete suppression of slavery in all its forms.” And the Universal Declaration of Human Rights, adopted unanimously by the United Nations in 1948, categorically bans the practice worldwide: “Slavery and the slave trade,” Article 4 proclaims, “shall be prohibited in all their forms.”

For most of human history, slavery was regarded as a universal fact of life. Now we regard it as an unspeakable crime and devote considerable resources to understanding, remembering, and discussing whether and how to make amends for what happened to enslaved people in the past.

Yet all the while, millions of human beings in the present — men, women, and children — remain enslaved.

According to a heartbreaking new report by researchers for the UN’s International Labor Organization and the human rights group Walk Free, 50 million people were living in some form of modern slavery last year, an increase of 10 million over the last five years. As the researchers use the term, “modern slavery” refers primarily to the forced labor in which nearly 28 million people — including 3.3 million children — are trapped, and includes another 22 million people in forced marriages, a condition that commonly encompasses sexual exploitation, domestic servitude, and violence.

The study’s findings are based on interviews with nearly 78,000 individuals across 68 countries. Since it was not possible to ask questions in some places where forced labor is known to be widespread, such as North Korea’s concentration camps and China’s Xinjiang region, the new report presumably understates the true scope of slavery in the 21st century.

It is a worldwide scourge. In terms of raw numbers, more than 29 million enslaved people live in Asian and Pacific countries. As a percentage of the population, the highest rates of slavery are in the Arab world, where it afflicts more than 10 of every 1,000 people. By no means is slavery confined to impoverished nations. “More than half of all forced labor occurs in either upper-middle-income or high-income countries,” the authors write, and it “touches virtually all parts of the private economy.” It is especially concentrated in five economic areas: manufacturing, agriculture, construction, domestic work, and the service sector.

To this day, human beings are still born into bondage because of debts accumulated by their parents or grandparents or because their forebears were captured and enslaved and became the property of the captors.

“People born into descent-based slavery face a lifetime of exploitation and are treated as property by their so-called ‘masters,’” explains Anti-Slavery International, which was founded in 1839 and is the world’s oldest abolitionist organization. “They work without pay, herding animals, working in the fields or in their masters’ homes. They can be inherited, sold, or given away… . Women and girls typically face sexual abuse and rape, and often have to bear their masters’ children. In turn, their children will also be owned by their masters.”

Equally appalling is debt bondage, which, according to the Council on Foreign Relations, accounts for half of all victims of modern slavery. Bonded labor often has the appearance of a contractual work arrangement but is designed to prevent the workers from ever clearing their debt. “The cycle often begins with a loan request made to a landlord or business owner for expenses incurred burying a family member, treating an illness, procuring employment, or staging a wedding,” the council notes. “The loan provider can then strong-arm laborers or threaten to take away their family’s shelter to extract more work than the value of the original loan. This can result in a family accruing debt over generations. Brick kilns, rice mills, farms, and embroidery factories are notorious hubs of debt-extorted labor.”

The new UN report describes the experience of Ran, an enslaved man in his 80s in an undisclosed country, whose bondage began when he was 16 and borrowed $20 from a landowner. To repay his debt, he was required to plow the landowner’s field — not for an hour or a day but for what turned out to be years. Another case is that of a 12-year-old girl named Jasmine, who was compelled to marry a man as payment for a debt owed by her father. Jasmine’s husband, an alcoholic, pimped her out to earn money to support his addiction.

Not even public slave auctions have vanished from the world. In 2017, CNN documented the ongoing operation of markets in Libya, where people, many of them migrants under the control of smugglers, were being offered to the highest bidder. In one location outside Tripoli, an undercover crew recorded the sale of a dozen men.

Slavery persists because it is lucrative. The International Labor Organization estimated in 2014 that “forced labor in the private economy generates $150 billion in illegal profits per year,” two-thirds of it from commercial sexual exploitation. Slavery also persists because it serves the interests of totalitarian rulers — from China’s use of forced labor to crush Uyghur Muslims to the sexual enslavement of Yazidi women and girls by Islamic State jihadists to Cuba’s policy of forcing thousands of doctors to provide medical services abroad under conditions so coercive that UN investigators liken them to slavery.

Modern slavery is not a secret. But it doesn’t get nearly the degree of attention or generate the level of outrage that it should. Journalists, academics, and activists spend a lot of time these days assigning guilt, promoting reparations, or waging ideological duels over slavery that no longer exists. Perhaps they should focus their energy into battling the slavery that is still all too real and holds 50 million human beings in its grip.