Even though the Soviet Union disappeared from the map more than a decade ago, the specter of communism remains hard for its successor countries to shake — especially in America. Our perceptions of Russia still gravitate toward the Cold War rivalry, from spy-novel plots to the 1980 US hockey team's “miracle on ice.”

The frosty US-USSR relationship certainly hasn't faded from family historians' memories. Nearly 3 million Americans have roots in Russia; another 1.5 million-plus claim ancestry in Ukraine, Belarus, Moldova, Estonia, Latvia and Lithuania. For decades, those who wanted to discover their family's past faced the ultimate brick wall: the iron curtain.