Three times in Anne Frank's widely read diary, the young Holocaust victim wrote about a tree. She could see it from the attic window of the secret annex where her family hid for two years, before being betrayed. The tree helped keep her hope alive.

"From my favorite spot on the floor I look up at the blue sky and the bare chestnut tree, on whose branches little raindrops shine, appearing like silver, and at the seagulls and other birds as they glide on the wind," she wrote on February 23, 1944. "As long as this exists, and it certainly always will, I know that then there will always be comfort for every sorrow, whatever the circumstances may be."

(READ what has become of the tree at CNN)