Written while she was in hiding during World War II, Anne Frank's Diary of a Young Girl is one of the most intimate accounts we have of life for European Jews during the Holocaust. It's also the journal of an ordinary adolescent girl—one who dreamed about crushes, was curious about her body, and made jokes about sex. As the Chicago Tribune reports, new analysis from Dutch researchers reveals two pages of what Frank described in her diary as "dirty jokes" that had been impossible to read until now.

A 13-year-old Anne Frank filled the pages on September 28, 1942 while living with her family in a secret annex in the Nazi-occupied Netherlands. Even under those stressful circumstances, she was able to keep her sense of humor. She wrote jokes like, "Do you know why the German Wehrmacht girls are in Holland? As mattresses for the soldiers." And, “A man had a very ugly wife and he didn't want to have relations with her. One evening he came home and then he saw his friend in bed with his wife, then the man said: `He gets to and I have to!!!"'

On the same pages as the dirty jokes, she included musings on sexual development, prostitution, and contraception. She wrote that a young woman's first period is "a sign that she is ripe to have relations with a man but one doesn't do that of course before one is married."

At some point during her two years in the annex, Anne decided to tape brown adhesive paper over the passages, presumably to save herself embarrassment in case anyone found her diary. It wasn't until 75 years later that researchers at the Anne Frank museum were finally able to decipher the text hidden beneath the covering. To do so, they photographed the back-lit pages and scanned them with image-processing software.

"Anne Frank writes about sexuality in a disarming way. Like every adolescent she is curious about this subject," Anne Frank House executive director Ronald Leopold said in a statement. He said that the texts "bring us even closer to the girl and the writer Anne Frank."

The first edition of Anne Frank's diary was published by her father in 1947, two years after she died in a Nazi concentration camp. It's since sold more than 30 million copies and has been translated into 67 languages. Due to copyright issues, it's unclear if the newly revealed text will make it into future editions.

[h/t Chicago Tribune]