Chicago. From worker rights rallies to marches for social justice, activists around the globe will kick off May Day demonstrations on Thursday.

In many countries, May 1 is a public holiday honoring labor. However, in the United States, activists say much of their message this year focuses on pushing back against former President Donald Trump's policies, particularly those targeting immigrants, federal workers, and diversity initiatives.

Thousands are expected to join demonstrations from Tokyo to Chicago. But in parts of the US, fear sparked by the Trump administration's policies is expected to keep some immigrants away.

"Everybody is under attack right now," said Jorge Mujica, a longtime labor leader in Chicago, where May Day rallies have historically drawn large crowds.

The Roots of May Day

The origins of May Day, or International Workers’ Day, trace back over a century to a pivotal chapter in US labor history.

In the 1880s, labor unions began demanding an eight-hour workday through widespread demonstrations and strikes. In May 1886, a labor rally in Chicago turned deadly when a bomb was thrown, prompting police to open fire. Several labor activists, most of them immigrants, were convicted of conspiracy and other charges; four were executed.

Unions later called for workers to be honored every May 1. A sculpture in Chicago's Haymarket Square commemorates the event with an inscription that reads, "Dedicated to all workers of the world."

Rallies and Riots

May Day rallies, marches, and sometimes riots have taken place worldwide in recent years, with unions demanding better worker protections, groups airing economic grievances, and activists calling for an end to the war in Gaza.

While most demonstrations are peaceful, some have ended in clashes with law enforcement.

Last year, police in Paris fired tear gas as thousands marched for higher pay and better working conditions. In New York City, May Day coincided with mounting tensions on college campuses over pro-Palestinian student encampments, leading to multiple arrests.

This year, organizers in several US cities, including New York, are calling for unity across various causes.

"We're organizing for a world where every family has housing, health care, fair wages, union protection, and safety, regardless of race, immigration status, or ZIP code," the American Civil Liberties Union of New York said in a statement.

Notable US events include a workers’ rally at Philadelphia City Hall with Sen. Bernie Sanders, as well as demonstrations in Los Angeles, Seattle, Washington, DC, and at the Colorado State Capitol.

Immigration Marches

While labor and immigrant rights are historically linked, May Day rallies in the US pivoted toward immigration issues in 2006, when roughly 1 million people, including nearly 500,000 in Chicago, protested proposed federal legislation that would have made living in the US without legal status a felony.

Since then, turnout has waned as advocacy groups shifted focus to other issues such as voting rights.

This year in Chicago, organizers plan to extend May Day activism through Cinco de Mayo, including boycotts and walkouts. While their focus remains on workers' rights, they’re also protesting what they say is rising anti-immigrant rhetoric from Trump.

Organizers acknowledge that Trump’s immigration enforcement efforts, particularly in sanctuary cities like Chicago, have created a chilling effect in immigrant communities. They anticipate lower turnout from immigrants but are expanding outreach to unions representing teachers and nurses.

"There's a lot of fear out there," said Omar Lopez, a veteran organizer in Chicago.

Worldwide Celebrations

May Day is a public holiday in countries such as France, Kenya, Russia, and China, where celebrations can last five days.

Elsewhere, the day is marked by seasonal festivities rather than political protests.

In Hawaii, May 1 is known as Lei Day, not an official holiday but a celebration of Hawaiian culture and the aloha spirit, typically involving the giving of flower leis.

In other places, people celebrate with May Day baskets filled with flowers and small gifts. In Annapolis, Maryland, the city will hold its 70th May Day Basket Competition, where residents and businesses vie for the most creative floral displays.

"It's our community's way of saying goodbye to winter and welcoming the beauty and energy of spring," said Annapolis Mayor Gavin Buckley.