Generations of children grew up with Curious George, but very few know the incredible true story behind his very first adventure – a daring escape from Nazi Germany.

The little-known tale of George and his creators, Hans and Margret Rey, is finally coming to light with the new mixed-media documentary Monkey Business by filmmaker Ema Ryan Yamazaki, who was granted unprecedented access to the Reys’ archives by their estate.

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“I actually grew up in Japan thinking George was a Japanese monkey, not realizing that every country was claiming him,” Yamazaki tells PEOPLE. “It’s really been a global phenomenon from the beginning.”

Hans and Margret Rey both came from Jewish families in Hamburg, Germany, where they became acquainted with each another as teenagers. When Hans moved to Brazil after World War I, Margret followed him and the two were married there in 1935.

“They took a vacation to Paris later that year,” Yamazaki explains. “What was supposed to be a four-week trip turned into four years – they just never checked out of the hotel.”

While in Paris, Hans and Margret completed the first manuscript for what would become Curious George. Hans was a gifted illustrator, and his wife, always a child at heart, helped him craft the prose.

Like so many other Parisians at the time, the Nazi invasion in 1940 caught the Reys off-guard. As Jews, their lives were at stake and they resolved to escape. But by the time Hans went looking for a pair of bicycles to flee Paris, everything was sold out.

“The only bike available was a tandem, a two-seater,” Yamazaki explains. “But Hans was able to build two separate bikes with spare parts.”

With their makeshift bicycles, the Reys made their way to the train station, where they were abruptly stopped by two large soldiers. At first, the soldiers told Hans and Margret they would not be able to leave. But after searching through their luggage and discovering the Curious George manuscript, the soldiers had a sudden change of heart.

“They were very lucky,” says Yamazaki. “They did have Brazilian passports but they were Jewish and there were some very close calls.”

They Reys were able to sell their bikes for train tickets and escaped the South of France to Lisbon, Portugal, where they made their way back to Brazil before securing American visas.

Within a year, the couple published their Curious George book with Houghton Mifflin Harcourt, at the time an upstart publishing house that purchased four stories from the Reys for the bargain price for $1,000.

“Meaning the first Curious George book was acquired for $250,” Yamazaki says with a laugh.

The couple, who the director says “were clearly true partners,” lived together in New York City and continued writing children’s books for the rest of their lives, with Margret taking the lead in turning Curious George into the global brand it is today.