They visited two of the encampments still standing today, where Africans faced conditions so wretched that hundreds of thousands died before even setting out on the passage to America.

Growing numbers of African-Americans are making the journey to these sites to walk the ground where their forebears suffered. For Griffin, a retired police officer, it was a deeply personal mission. His grandfather, Robert Griffin, was born into slavery in Mississippi in 1862.

"He was a wonderful gentleman," he says of his grandfather. "And his father and mother were slaves. And that's not too far removed from me today."

CRYING SURF

The first stop on the tour was Cape Coast Castle, which the British presided over during the peak of the slave trade in the 1700s.

Hundreds of Africans at a time were thrown into one of its dark, hot dungeons, where they would live for months in utterly inhumane conditions. They were forced to fight over the scarce food and water and were left to live in their own waste.

A guide named Harry Blankson explains to the tour how food and water was dropped through a small hole. "Water is thrown, they cup their hands and get a sip," he says. "They eat, they drink, they vomit, urinate, defecate, and sleep in it here."

Williams, a former postal worker, was stunned at how the Europeans lived comfortably in quarters above the sweltering prisons, which had only tiny openings for air. Like Griffin, she feels a profound connection to those who suffered there under the harsh European oppressors. "They did not connect with us as humans. We're no more than the dirt on the ground," she says.

Griffin says, "It just tears your soul up to know that possibly your ancestors came through this very same dungeon."

From the chamber there is a narrow passageway that leads to the ocean — now hauntingly dubbed "The Door of No Return." Captives were herded through the passage to ships which carried them away from everything they had ever known.

According to Blankson, many visitors today insist the screams of the captives can still be heard in the waves.

"It was almost as if there were people in there," says Williams. "I could actually hear voices. It was just like wailing, just wailing and crying."

RAPE AND STARVATION

The next stop on the tour was Elmina Castle, which was once run by the Dutch.

Tour guide Charles Adu-Arhin says visitors are most moved by the female dungeons at Elmina, where European officers sometimes raped their African prisoners.

Officers would choose their victims from a balcony as the female captives were routinely paraded through a courtyard below. "That was the only time the women were allowed out," says Adu-Arhin.

A chosen woman would be then sent off to be cleaned and later brought through a trap door into an adjoining room where she would be raped. There was a twist to these dreadful acts. If by chance, she became pregnant, she was set free and allowed to remain in Africa.

In the courtyard is a cell that was used for prisoners who tried to rebel against their captors. These men were condemned to death and left to starve. Across the way, standing in ironic juxtaposition, is the church where the European officers worshiped.

HEALING THE WOUNDS

"I had no idea it would be this bad," says Griffin. "I mean, it's just those dungeons were just like an oven."

He points out that Africans suffered at Elmina and Cape Coast and the other slave sites. "For 300 years human beings were beaten and raped and just every foul thing you can run through your mind happened to them," he says.

The visit is emotionally fraught for the visitors, but by nightfall, there was a chance for some healing. Nana Okofo, an American living in Ghana, led a spiritual ceremony.

"So we're going to go through this 'door of no return,'" he tells Williams' and Griffin's group, "but we're going to turn right around and come back in."

Griffin says his thoughts turned towards to his grandfather and his African ancestors.

"The thought that went across my mind was, I am walking into the same footsteps that perhaps some of my relatives passed through," he says.

After a few solemn moments on the beach, these African-Americans did what their ancestors were never free to do — they returned back through the door, singing, "We are home once more."