PORTLAND — City Hall’s shadow crept across the sidewalk toward Congress Street as over 100 people gathered to honor the power and sacrifice of workers, joining thousands of activists around the globe who recognized International Workers’ Day and May Day on May 1.

The May Day rally at City Hall’s doorstep, which kicked off around 5 p.m. on Friday, was organized by the Maine Service Employees Association, Local 1989 of the Service Employees International Union, which represents over 13,000 active and retired Maine workers across nearly two dozen employers in the public and private sectors.

The day not only provides an opportunity for laborers to advocate for their rights but also to honor those who stood up and spoke out before them.

While aligned with International Workers’ Day, May Day is rooted in the United States, said Mark Brunton, union president.

“It was born right here in this country on the 1st of May 1886, when hundreds of thousands of workers walked off the job in Chicago and across the United States, demanding one simple thing: an eight-hour day,” Brunton said, prompting applause from demonstrators. “Eight hours for work, eight hours for rest, eight hours for what we will.”

May Day also honors the workers killed in the Haymarket riot in Chicago three days later.

Jesse Hargrove, social studies teacher and Maine Education Association president, noted, “The roots of May Day can be traced right here to Maine.”

“Particularly, Portland, Maine,” he said.

In 1847, Hargrove said, overworked Portland ship carpenters organized.

“They launched a strike to win 10-hour days, leading to the formation of the Mechanics and Laborers Association,” he said. “Shipyard workers in Bath later also secured a 10-hour workday.”

These early movements eventually led to legislative reforms, the educator said.

U.S. Senate candidate Graham Platner, the presumptive Democratic candidate after Gov. Janet Mills suspended her campaign on Thursday, capped off a series of speakers that included an array of Maine Democrats vying for state and federal offices.

The oyster farmer and military veteran from Sullivan used the history of the labor movement as an allegory for the organization required for the working class to take on today’s challenges.

“They were sacrifices of people who understood that there was absolutely no way the system around them was going to change unless they banded together and fought back,” Platner said. “This nation has seen many moments of crisis for our democracy … in every single one of these moments, the Americans who rose to the occasion to protect the project, they understood that they could not go back to what they had. They needed to build something new.”

At one moment in his roughly 11-minute speech, Platner choked back tears.

“I can’t tell you how much emotion this gathering brings me today,” he said. “Seeing this many people down here in Portland, this many Mainers, coming out to support each other and to support organized labor in their constant battle.”

The rally in Portland on Friday also acted as a way for some union workers to get their message out.

Kerem Gungor, a senior environmental engineer at the Maine Department of Environmental Protection; Charlie Guy, a project manager at the Maine Department of Transportation’s bridge program, and their fellow MSEA-SEIU Local 1989 members have been working without a contract for 10 months.

“In the public sector, we’re prohibited from striking. We can’t fight for ourselves,” Guy said in an interview.

Both said they and many of their colleagues are struggling — “look at the gas prices,” Guy emphasized — and with their current wages, employers are finding it difficult to retain workers. In their industries, they said, workers can make higher wages in other parts of the country.

“Organizing is tremendously important,” Gungor told a reporter. “People coming together, like today, and expressing what they want.

“There’s strength in numbers.”