Photo historian: In the late 1930s; Roman Vishniac crisscrossed the continent photographing the doom

CANADA - DECEMBER 18: Photo historian: In the late 1930s; Roman Vishniac crisscrossed the continent photographing the doomed Jews of Europe. Now; he says; he'd love to do it again. But the only country where I am needed as a photographer is the only country where it is impossible -Soviet Russia. (Photo by Boris Spremo/Toronto Star via Getty Images)