Anne Frank musical in the works in Spain

The Diary of Anne Frank, the most widely read book on the Holocaust, which has been rewritten for plays, movies and TV dramas, is now being made into a Spanish musical.

On Friday, a theater troupe visited the tiny Amsterdam apartment where the Jewish teenager hid from the Nazis, seeking inspiration for their characters and the show.

The Anne Frank Museum has endorsed the concept and guided the 22-member cast and directors through the space where the Frank family hid during the German occupation of the Netherlands in World War II.

"If you're doing a musical of the family and how they lived and the house and everything, I think it's very special and a very important detail to come to this house," said Isabella Castillo, 13, who plays the part of Anne Frank.

She said she was struck by the size of the apartment - even smaller than she imagined it

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An inspirational, tragic opera-like play

Her story might not seem a likely candidate for a musical, but Rafael Alvero, who developed the concept, said the show is inspirational, and comparable in mood to a tragic opera.

"When I first came here they had this doubt, about how somebody can do a musical of a story like this?" said Alvero, who worked on the concept for a decade.

"Of course this (staging) is emotional," he said. "The thing we want to do is ... Through the music, to understand the story better."

Castillo, who lived in the United States until she was scouted for the part of Anne, said she felt honored with the role: "There are things I have in common with Anne… when I started reading the diary - sometimes you get the feeling that you're not alone," she said.

The similarities go further: The Frank family emigrated from Germany to the Netherlands in 1933, when Anne was four. Castillo's mother defected from Cuba while Isabella was a toddler, and they lived in hiding briefly in Belize before immigrating to Miami.

During the tour in the early morning hours before the museum opens to the public, actors wondered what happened to the Franks' furniture.

Museum historian Menno Metselaar explained that after the Nazis raided the annex, Dutch collaborators cleaned it out and sold everything of value.

Anne's father Otto Frank, who survived the war, felt that refurnishing the space would amount to falsifying history.

Practical reasons would prevent it anyway, Metselaar said: One million tourists visited the museum in 2007, and adding furniture to the tiny rooms would make it impassable.

Members of the cast said they felt moved at seeing the space they had imagined many times: "When I was coming in, I started to feel touched by everything I saw, and I thought that wouldn't happen," said Rocio Leon, playing the part of Anne's sister Margot.

The cast also sang several numbers from the show, due to open in Madrid's Calderon Theater on February 28, to an enthusiastic reception by museum staff.

Anne Frank kept her diary for 25 months while she and her family hid inside a "secret annex" atop a canal-side warehouse.

The family was betrayed and arrested in August 1944 and Anne Frank died in the Bergen-Belsen concentration camp in March 1945. Her diary was preserved and later published and has now been read by millions of people.