The Zookeeper's Wife by Diane Ackerman

When Germany invaded Poland, Stuka bombers devastated Warsaw—and the city's zoo along with it. With most of their animals dead, zookeepers Jan and Antonina Zabinski began smuggling Jews into empty cages. Another dozen "guests" hid inside the Zabinskis' villa, emerging after dark for dinner, socializing, and, during rare moments of calm, piano concerts. Jan, active in the polish resistance, kept ammunition buried in the elephant enclosure and stashed explosives in the animal hospital. Meanwhile, Antonina kept her unusual household afloat, caring for both its human and its animal inhabitants—otters, a badger, hyena pups, lynxes.

Very interesting story.  

I know it's a true account, but I would have preferred it to be told like a story rather than read like a history text.