Anne Frank's marbles to go on display in Rotterdam

Shortly before she and her family went into hiding, Anne Frank gave some of her toys to a friend for safekeeping -- a tin of marbles, a tea set and a book.

Anne had regularly played with Toosje Kupers on the streets of their Amsterdam neighborhood and tasked her friend with looking after her treasured possessions.

The next part of the story is well known -- the Frank family's suffocating experience of spending 25 months in cramped quarters, hiding from Jewish persecution by the Nazis. The world learned the harrowing tale in Anne's own words, written in her now widely read diary.

Now, some 70 years later, Frank's colorful marbles have been rediscovered and will go on display for the first time at a World War II exhibition in Rotterdam.

"Anne gave these to her friend for safe-keeping," Teresien da Silva, head of collections at the Anne Frank House museum, told CNN. "She kept them for when Anne returned, but Anne did not return."