Deep inside a vast storage vault at the Museum of Fine Arts is a tiny Flemish painting, a 16th-century artwork that has been largely unseen and undisturbed for most of the last 80 years.The painting, “Landscape with Burning City,” by Herri Met De Bles, depicts a lone traveler fleeing a city in flames. The cruel irony is how the image mirrors the painting’s own extraordinary journey.Just 5 inches tall, the Met De Bles picture was once part of a celebrated European collection amassed in the early 20th century. Later subsumed by the Nazi war machine, it found its way into...