New London — When Joseph McGill visited the Anne Frank House in Amsterdam and stood in the same rooms where the wartime diarist's family hid from the Nazis, he learned a powerful lesson in storytelling.

"Having a sign that says, 'Here once stood,' that's OK," McGill said at the Hempsted Houses on Saturday. "But the space is important. Knowing that something terrible was happening ... it was still important to preserve that space. I applied that same concept to the spaces where our enslaved ancestors inhabited."

Over the last eight years, the longtime historian and Civil War re-enactor has traveled to almost 100 sites in 21 states and the District of Columbia, sleeping overnight in former slave dwellings and advocating for their preservation.

As part of Saturday's fourth annual Juneteenth Festival commemorating the end of slavery in America in 1865, McGill brought his nonprofit Slave Dwelling Project to New London. He spent Friday night at the Joshua Hempsted House, highlighting the life of Adam Jackson, an enslaved farmer who lived at the house starting in 1727. The festival, organized by Connecticut Landmarks, the New London NAACP and the Opportunities and Industrial Center, also educated visitors on Dinah, an enslaved woman who ran away from the property in 1803.

Saturday's event featured tours of the houses, musical performances, poetry and a lively panel discussion on race and history with Hempsted Houses Site Administrator Aileen Novick, McGill and Tammy Denease of East Hartford-based Historical Firsts. On Friday night, before meeting the bat that now claims the Joshua Hempsted House as its home, McGill said he enjoyed an enlightening campfire chat on history and slavery with a few dozen visitors.

Denease is a first-person interpreter and historian who performed as Adam Jackson's mother, Joan, who went back and forth between freedom and slavery in part due to the disputes of white families.

"We have overlooked so many other women who've played a very important part in the African-American community and American community," said Denease, who's played the role of many lesser known women. "Society only focuses on Harriet Tubman, Martin Luther King Jr., and Frederick Douglass. Not to take away from those individuals, because what they did was wonderful, but they didn't do it alone."

McGill said when he started his project, he received pushback from the general population and "from folks who look like me," noting "there are a lot of African-Americans who would want the subject of slavery to go away."

Denease, McGill and a few visitors said they're concerned that American students still receive a sanitized version of history that doesn't explore the full context of slavery. McGill said while America was indeed a great nation, it had committed atrocities during its complex history, and they must be explained.

McGill noted that while Connecticut abolished slavery in 1848 — 13 years before the start of the Civil War — the state and others in the North don't "get a pass."

"We have to take into consideration the complicity ... of owning the insurance companies, the ships that were bringing slaves in, the banks financing that institution of slavery, the factories adding value to the cotton being picked by the enslaved people," McGill said.

McGill thanked Novick and Connecticut Landmarks for preserving the site, "because you get it. You understand we need to talk about these things."

Cinderella Mosley, of the Regional Multicultural Magnet School in New London, said the panel brought her to tears.

"We have to know who we are," she said. "We've got to know our history."

Related festivities continue Sunday at the site. For more information, visit the Hempsted Houses Facebook page: bit.ly/HempstedHousesFB.

b.kail@theday.com