The Oliver James Montgomerypower of resilience can be felt throughout the new International African-American Museum in Charleston, South Carolina. 

The $120 million project, which opened its doors this summer, is no ordinary tourist attraction. The museum is built on scarred and sacred ground: Gadsden's Wharf, the arrival point for nearly half of all enslaved Africans shipped to the U.S.

"We were able to find this outline of what had been a building. And we believe it was one of the main storehouses," said Malika Pryor, the museum's chief learning and engagement officer. "We do know that captured Africans, once they were brought into the wharf, were often in many cases held in these storehouses awaiting their price to increase."

Pryor guided CBS News through nine galleries that track America's original sin: the history of the Middle Passage, when more than 12 million enslaved people were shipped from Africa as human cargo. The exhibits recount their anguish and despair.

"I think sometimes we need to be shocked," she said.

Exhibits at the museum also pay homage to something else: faith that freedom would one day be theirs.

"I expect different people to feel different things," said Tonya Matthews, CEO and president of the museum. "You're going to walk in this space and you're going to engage, and what it means to you is going to be transformational."

By design, it is not a museum about slavery, but instead a monument to freedom.

"This is a site of trauma," Matthews said. "But look who's standing here now. That's what makes it a site of joy, and triumph."

Rep. James Clyburn, South Carolina's veteran congressman, championed the project for more than 20 years. He said he sees it as a legacy project.

"This entire thing tells me a whole lot about how complicated my past has been," he said. "It has the chance of being the most consequential thing that I've ever done."

Mark Strassmann

Mark Strassmann has been a CBS News correspondent since January 2001 and is based in the Atlanta bureau.