In some countries, it's a public holiday honoring labor, but in the U.S., activists will use the day as a call to action against President Trump's policies.

Chicago was one of hundreds of cities across the country where people took to the streets to mark May Day, a holiday with deep roots in the city’s labor history.

Thousands of people attended May Day protests across the country Thursday in response to the Trump administration’s controversial moves against immigrants and federal workers over its first 100 days.