2021 marks the 109th year since the "unsinkable" Titanic hit an iceberg and sank in the Atlantic Ocean, and thousands of lives were lost in frigid waters.

The 1997 blockbuster film Titanic showed the luxurious lifestyle of the upper class and a heart-wrenching romance between two young lovers. But few know that among the passengers, there were actually eight Chinese, and six survived the disaster.

What happened to them, and where did they go? Why have they been forgotten for so long? The documentary The Six: The Untold Story of RMS Titanic's Chinese Passengers seeks to provide answers.

The six Chinese survivors

Eight Chinese sailors boarded the third class cabin of Titanic on April 10, 1912 at Southampton Port in the UK, with tickets purchased by their employer.

Only four days later, an iceberg in North Atlantic Ocean struck Titanic and the ship began to sink. Several gates leading to the first-class cabin, where lifeboats were placed for emergency use, were not opened promptly, leaving third-class passengers fending for themselves.

Among the six survivors, Lee Bing, Chang Chip, Ling Hee and Ali Lam boarded a folding lifeboat together. Chong Foo got on the last lifeboat, just before Titanic sank completely. Fang Lang (also known as Fang Rongshan in Mandarin), the last survivor, grabbed a door and floated on open water before he was rescued.

"I've always admired the Chinese guy on the door, or on the piece of wood. That became the inspiration of how Rose was saved," said James Cameron, producer of The Six and director of Titanic.

"Six out of eight Chinese passengers survived, that's a 75 percent (survival rate)", said Arthur Jones, director and writer of The Six.

"So it shows a certain ingenuity and inventiveness. They had their hopes and their dreams as well and they were traveling across the ocean to realize that," adds Cameron in the film.