ALEXANDRIA, Va. - Imagine coming to a cemetery kept secret for a century, and finding ancestors you never knew existed.

"I am so proud," said Zuny Matema. Proud because of who they were.

Most of the people buried in the Contrabands and Freedmen Cemetery in Alexandria, their names now etched in bronze, were former slaves and children who escaped to freedom during the Civil War.

Matema's relatives descended from Martha Washington's maid.

"To actually see your ancestors name is, oh my god," she said.

The dedication of the cemetery happened almost by accident. Alexandria was a gathering place for escaped slaves during the Civil War. But after the war, with no headstones on the graves, the city found a way to forget. In the 1950s, a gas station was allowed to pave it over....