In the 20th century, many burial grounds across the country succumbed to highways and sprawl. African American gravesites were particularly vulnerable.

The busy intersection of Guinea Road and Little River Trunpike in Fairfax County, Va. -- less than 20 miles from Washington, D.C. -- bears little resemblance to a historic site. No manors, plaques or guided tours mark this nondescript suburban corner, just the letter "G" painted on the siewalk and several tiny orange flags in the dirt. Beneath the sidewalk, however, are at least two rows of grave shafts (hence the letter "G" for graves) most likely containing the remains of African Americans -- 29 burials in all, some predating the Civil War.  (piece cited but not available on-line)