I just finished reading an article in the latest issue of National Geographic Adventure. It told of the struggle of 38 Jews living in the Ukraine during the Holocaust. Their area was declared "juden-frei," or free of Jews, by the Nazis. They escaped by hiding themselves in what is probably the world's 10th largest cave called the Priest's Grotto. They stayed underground for 344 days straight, with only a few of them leaving occasionally at night to forage for supplies.
Pick up this issue and read it if you get a chance. It's a fascinating story of how one extended family survived a horrible experience. For more information, you can read an interview with one of the cavers who returned to the site, Chris Nicola, at the National Geographic Adventure website.