In 1941, in German-occupied Poland, the Nazis began abducting members of the Jewish population and imprisoning them in extermination camps.
But there were exceptions.
The Nazis held foreign passport holders in detention camps to be traded later for Germans detained abroad.
With this loophole in mind, Aleksander Wadosz, a Polish diplomat in Switzerland, started producing forged Latin American passports and smuggling them to Polish Jews.
In the end, these simple paper booklets would mean the difference between life and death for thousands.
A striking thing about passports is that they're actually a relatively new invention.
They're not the first form of travel documents.
In ancient Egypt, travelers carried letters of safe conduct issued by rulers,
In Han China and Tudor England, foreigners were issued travel passes, and in the 19th century, poorer migrants often needed health certificates to enter the U.S.
However, for much of human history, borders have been relatively fluid, and travel lacked bureaucratic requirements.
But when World War I broke out in 1914, everything changed.
Neighboring countries and their colonies became wartime enemies.
To deter both espionage and desertion, many European nations established checkpoints at ports of entry to confirm travelers' nationalities.
Here, authorities would screen early versions of passports, which, depending on the issuing country, were documents that followed different formats and contained varying types of information.
When the war ended, many expected nations to remove passport requirements,
In 1920, the newly established League of Nations discussed this, but in light of other post-war concerns, such as safeguarding national security, preventing the spread of epidemics, and managing the movement of refugees, they opted to temporarily keep the passport system.
To ease travel, they encouraged countries to follow international passport guidelines, using booklets of standard size and layout, written in the language of the issuing country and French.
But beyond this, every country was free to determine what approvals or documents a person needed to cross its borders.
This included rules around issuing visas, the legal permissions dictating how long a person can stay in a country, and what they can do, such as work or study.
And by 1926, when the League of Nations met again, the idea of abolishing passports had lost momentum, solidifying the passport system we know today.
However, this system brought new problems with it.
Passports were used not just to monitor movement, but also as tools of power and control.
They reinforced hierarchies between citizens born in colonizer states and those born in the colonies.
For example, in the 1920s, UK-born British subjects could get British passports, while Indian-born subjects could receive a distinct British Indian passport.
And since passports are issued by governments, they could be withheld from citizens as punishment or to discourage dissent.
During the Cold War, the U.S. revoked the passports of political and civil rights activists, like W.E.B.
Du Bois.
As passport monitoring was largely relocated into airports in the second half of the 20th century,
Advances in digital tracking and databases allowed governments to more tightly regulate and control individual movement.
Today, a passport's strength and where a person can travel to and from are often dependent on relationships between countries.
There can be regional agreements, like the Schengen Agreement, which allows border-free travel within 29 European countries.
Higher-income countries also typically have better travel access.
The result is a system that privileges citizens of certain countries while constraining others.
As of 2025, a U.S. passport holder can enter almost 180 countries without arranging a visa beforehand.
For a Pakistani passport holder, that number drops below 40.
And these disparities extend to a person's chances of securing a foreign visa.
For example, in 2024, Algerian applicants for U.S. visitor visas faced a much higher refusal rate than Brazilian applicants.
In some places, money can buy you access.
More than a dozen countries offer Golden Passports programs that grant citizenship, and therefore passports, to people who make a significant investment or donation.
As the world becomes increasingly global for some and increasingly divided for others, the question remains, should lines on a map determine a person's rights and freedoms?
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