Back in the 1970s, when the first African American rangers arrived at Independence National Historical Park, they quickly noticed that little of their own heritage appeared in stories told at famous park sites.It rankled, and one of them argued that the narratives should be more inclusive. "Hey, we need to get some more diverse stories going here," he urged, according to Joe Becton, a park ranger since 1986. But, says Becton, it "didn't have much impact."In the early 1980s, Charles Blockson, curator of the Blockson Afro-American Collection at Temple University, argued that at least the abolitionists, who named the Liberty Bell and transformed it into an antislavery symbol, should get a nod. The park eventually agreed, but in the view of many, that nod often amounted to only cursory mentions at the old Liberty Bell pavilion.In the 1990s, a new management plan acknowledged that African American history should be a part of park offerings, and suggested African American programming for Washington Square. Again, not much happened.But since 2002 - when controversy erupted over slavery in George Washington's household and the park's failure to acknowledge it - a great change has swept over Independence Park.Becton now conducts popular Underground Railroad walking tours.Liberty Bell visitors now hear about abolitionism, slavery, women's rights, immigrant struggles, human rights around the world - and the role the bell has played in all.The National Constitution Center now displays African American artifacts found during the archaeological excavation that preceded the center's construction. A private organization, it has presented programs and exhibitions of particular significance to African Americans and is part of the city's Quest for Freedom trail, which traces the course of the Underground Railroad.In a year or so, according to officials there, visitors at the African American Museum of Philadelphia a block off Independence Mall on Seventh Street will see a new permanent exhibition on 18th- and early-19th-century black life in Philadelphia.SOURCE: PHILADELPHIA INQUIRER