(CNN) A mile from where ships dropped shackled Africans off by the thousands and inside a city hall built by forced labor, council members gathered Tuesday to finally apologize for Charleston's role in the slave trade.

For the South Carolina city, the apology has been in the works for a long time. The City Council picked Tuesday to approve the resolution because it's Juneteenth -- a day that celebrates the abolition of slavery.

"The vestiges of slavery still plague us today," Councilman William Dudley Gregorie told CNN affiliate WCBD . He brought the bipartisan resolution to the council.

"Either way, up or down, it will show the world -- it will give the world a barometer of where we stand as a city in the 21st century as it relates to racial reconciliation," he said.

"The institution of slavery did not just involve physical confinement and mistreatment," it says. "It also sought to suppress, if not destroy, the cultural, religious and social values of Africans by stripping Africans of their ancestral names and customs, humiliating and brutalizing them through sexual exploitation, and selling African relatives apart from one another without regard to the connection of family, a human condition universal among all peoples of the world."

Slavery's role in Charleston's history

Slavery riddles the history of the South Carolina city.

About a mile away from City Hall is Gadsden's Wharf, where slave ships docked and unloaded at least 100,000 slaves. (In 2020, the site will become the home of the International African-American Museum).

The entrance to the Old Slave Mart in Charleston, believed to be the site of the last slave auction facility in South Carolina

And, as the resolution says, slave labor was "fundamental to the economy of colonial and antebellum Charleston."

Decades after desegregation and the end of the Jim Crow era, Charleston's racist past simmers.

It's one of many places in the US grappling with whether to remove nods to the Confederacy. A statue of John C. Calhoun, a staunch defender of slavery and secession, still stands in a city square.

This 2015 photo shows the location where Gadsden's Wharf once stood

Earlier Tuesday, Councilman Keith Waring, an African-American, said the resolution in its current state has no substance, and he wouldn't vote for it. It wasn't immediately known how he voted that night.

"If we vote for it today, how are we going to be better off tomorrow or the next day?" Waring told CNN. "Without a substantive change in policy, the proposal is hollow."

But, along with the apology, the resolution calls on the city to promote equality in city businesses, to memorialize African-Americans' graves and to create an office of racial reconciliation.

For that, says Charleston NAACP President Dot Scott, the apology is worth backing.

"Regardless of where it came from," she told CNN, "it sends a message."