WASHINGTON – It will be the rarest of sights: a black-hulled, two-masted replica of a slave-carrying schooner slipping into Havana's harbor flying two flags — those of the United States and Cuba.

That's how it is for the Amistad, a symbol of both a dark 19th century past and modern public diplomacy.

The Amistad is the 10-year-old official tall ship of the state of Connecticut and a replica of the Cuban coastal trader that sailed from Havana in 1839 with a cargo of African captives, only to become an emblem of the abolitionist movement.

As a U.S.-flagged ship, the Amistad's 10-day, two-city tour of Cuba provides a counterpoint to new and lingering tensions between Washington and Havana and stands out as a high-profile exception to the 48-year-old U.S. embargo of the Caribbean island.

For the Amistad, Cuba also represents a final link as it retraces the old Atlantic slave trade triangle, making port calls that are not only reminders of the stain of slavery but also celebrations of the shared cultural legacies of an otherwise sorry past.

When it drops anchor in Havana's harbor on March 25, the Amistad will not only observe its 10th anniversary, it will commemorate the day in 1807 when the British Parliament first outlawed the slave trade.

The powerful image of a vessel displaying home and host flags docking in Cuba is not lost on Gregory Belanger, the CEO and president of Amistad America Inc., the nonprofit organization that owns and operates the ship.

We're completely aware of all of the issues currently surrounding the U.S. and Cuba," he said. "But we approach this from the point of view that we have this unique history that both societies are connected by. It gives us an opportunity to transcend contemporary issues.

It's not lost on Rep. William Delahunt, either. The Massachusetts Democrat has long worked to ease U.S.-Cuba relations and he reached out to the State Department to make officials aware of the Amistad's proposal.

U.S.-flagged ships have docked in Havana before, but none as prominently as the Amistad. The Treasury's Office of Foreign Assets Control has periodically approved Cuba stops for semester-at-sea educational programs for American students, and the Commerce Department has authorized U.S. shiploads of exports under agriculture and medical exemptions provided in the Trade Sanctions Reform Act of 2000.

Obviously we have serious differences, disagreements," Delahunt said. "But in this particular case the two governments, while not working together, clearly were aware of the profound significance of this particular commemoration.

The Amistad's visit comes as international tension over Cuba's human rights has heightened since the Feb. 23 death of Orlando Zapata Tamayo after a long hunger strike in jail. Another dissident, Guillermo Farinas, has refused to eat or drink since shortly after Zapata Tamayo's death. He is not imprisoned, though, and is allowing himself to be fed intravenously. Both men are of African descent.

I would hope — it isn't going to happen — that the ship would go into Havana harbor with a flag at half staff representing what happened on the history of that ship and what is currently happening in Cuba in terms of the violations of human rights," said Andy Gomez, a senior fellow at the University of Miami's Institute for Cuban and Cuban-American Studies.

The original Amistad's story, the subject of a 1997 Steven Spielberg movie, began after it set sail from Havana in 1839. Its African captives rebelled, taking over the ship and sending it on a zigzag course up the U.S. coast until it was finally seized off the coast of Long Island. The captured Africans became an international cause for abolitionists; their fate was finally decided in 1841 when John Quincy Adams argued their case before the Supreme Court, which granted them their freedom.

Miguel Barnet, a leading Cuban ethnographer and writer who has studied the African diaspora, said it is only appropriate that the new Amistad would call on the place of the original ship's birth. Indeed, he said in an interview from Cuba on Wednesday, it is the horror of the slave trade that left behind a rich common bond — not just between the United States and Cuba, but with the rest of the Caribbean — that is rooted in Africa.

That's why this is an homage to these men and women who left something precious for our culture," he said.

The new Amistad has crossed the Atlantic and wended its way through the Caribbean since 2007. It has worked with the United Nations and UNESCO's Slave Route Project. Using high technology hidden in its wooden frame and rigging, the ship's crew of sailors and students has simulcasted to schools and even to the U.N. General Assembly.

It will do so again — with Cuban students — from Havana.

It's about enlivening the history," said Steve Schwadron, Delahunt's former chief of staff and a consultant on the Amistad project, "and not just as a stale book.

(This version CORRECTS that U.S. embargo on Cuba is 48 years old, not 47.)