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.

Labor rallies in large cities swelled with demonstrators focused on immigration, education and worker’s rights. But protesters also rallied at small-town schools and city halls in Trump country.

Thousands are expected to march through Chicago today for May Day, demanding workers' rights, immigrant protections and better workplace conditions.