Risque jokes hidden in Anne Frank’s diary have been discovered over 70 years after the publication of "The Diary of a Young Girl," the Anne Frank House announced Tuesday.
Researchers in the Netherlands found two pages of the then 13-year-old’s diary, with the red-checked cover, were covered up with brown masking paper.
Researchers used image technology to highlight text on the pages, making them legible.
The hidden pages included crossed-out phrases, "dirty" jokes and lines about sexual education, according to The Associated Press.
According to the Anne Frank House, the teen often heard jokes told around the secret annex where she lived and could often hear similar jokes on the radio.
Experts said the jokes helped break tension in the hiding place, the Washington Post reports.
Frank also made a list of 12 signs of beauty and assessed how well she lined up with them.
It’s a sign, the museum said, of the young girl’s analysis of the world around her and shows her "inquisitive" and "precocious" personality.
The Anne Frank Museum said it is unclear why she hid the pages so carefully, but it may have been to hide the pages from her father, who she wrote threatened to take away the diary.
It may also have been because Anne Frank regularly re-read her diary entries and made changes to them.
Anne Frank’s diary documented the 25 months she spent hiding from the Nazis with seven others in a secret annex in Amsterdam from 1942 to 1944.
The family was seized by the Gestapo and taken to a concentration camp when Anne Frank was 15 years old.
She died of typhus at the Bergen-Belsen concentration camp in Germany in 1945, only a few weeks before British soldiers liberated the concentration camp.
Anne Frank’s father, Otto Frank, was the only one to survive.
"The Diary of a Young Girl" was first published after the end of World War II and transformed the young girl into a universal symbol of hope.
The newly discovered diary entries are now included in academic research into the diaries of Anne Frank and her development as a writer.