Anne Frank's marbles, currently on display at the Kunsthal Art Gallery in the Netherlands. (AP Photo/Anne Frank House Amsterdam, Diederik Schiebergen)

In 1942, Anne Frank was worried about losing her marbles. According to the Associated Press, Anne Frank gave some of her toys to a non-Jewish friend who lived next door in Amsterdam before she and her family went into hiding. The friend, Toosje Kupers, explained that marbles were not particularly valuable, but that she agreed to take care of them—and Frank’s cat Moortje—at Anne’s request.

“‘I’m worried about my marbles, because I’m scared they might fall into the wrong hands,'” Kupers said Anne told her. “‘Could you keep them for me for a little while?'”

Kupers, now 83, wouldn’t have known then that the Frank family would never return and that Frank would die in the Bergen-Belsen concentration camp in March 1945, a few months shy of her 16th birthday. She held on to Frank’s marbles, a tea set, and a book, though, until last year, when she decided to approach the Anne Frank House in Amsterdam with the objects.

The marbles are now in Rotterdam for an exhibit called “The Second World War in 100 Objects,” which opens today at the Kunsthal Art Gallery. The marbles will be on display through May 5, 2014.

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