What 2016 historical monster film, directed by Zhang Yimou and starring Matt Damon, depicts European mercenaries helping Chinese soldiers defend against mythical creatures at the Great Wall of China?

The 2016 historical monster film that sees European mercenaries joining Chinese soldiers to defend the Great Wall (Review) against mythical creatures is titled "The Great Wall". Directed by the acclaimed Chinese filmmaker Zhang Yimou, known for his visually stunning epics like "Hero" and "House of Flying Daggers", the movie features Hollywood star Matt Damon in a leading role. This ambitious co-production brought together American and Chinese talent to create a large-scale fantasy adventure.

The plot centers on two European mercenaries, William Garin (Matt Damon) and Pero Tovar (Pedro Pascal), who are searching for gunpowder in China when they encounter a secret military order defending the Great (Review) Wall. They quickly discover that the Wall's true purpose is not to keep out human invaders, but rather a horde of monstrous, alien-like creatures called Taotie, which attack every sixty years. Garin, a skilled archer, finds himself drawn into the conflict, fighting alongside the elite Chinese warriors of the Nameless Order, led by Commander Lin Mae (Jing Tian).

"The Great Wall" was notable for being Zhang Yimou's first English-language film and the most expensive film ever shot entirely in China at the time of its production. The film aimed to blend Hollywood blockbuster sensibilities with elements of Chinese culture and storytelling, showcasing elaborate battle sequences and vibrant visual aesthetics characteristic of Zhang's directorial style. While the actual Great Wall of China could not be used for filming, three extensive replica walls were constructed for the movie's production, involving over a thousand crew members and taking more than three years to complete.