Everything Is Illuminated; by Jonathan Safran Foer.

Someone young goes into unknown territory, one moreover that has been demonised where he grew up, for sake of looking up a vital piece of the past, someone who had saved his grandfather from being captured and carried to death if not killed outright. To thank someone who existed once -

Gratitude is a rare virtue, and this tale a moving example of gratitude at its best, when one may not find the person to be thanked however belatedly. Belatedly it had to be, because of the various closed borders.