‘The Great Wall’ is showing at the Sonoma 9 Cinemas. Rated PG-13. Running time 1:46. Visit cinemawest.com.

Appropriately enough, the titular Great Wall is visible from outer space, at least the version of outer space you see in the animated Universal logo.

Matt Damon plays the soldier of fortune William Garin. William accidentally runs right into that big wall while trying to find a sample of a mysterious new technology—gunpowder—that will make him rich in the west. With him is Tovar, an old mercenary pal from Spain.

The wall is protected by the Nameless Order who are decked out in bright costumes according to their specialties (red is for archers, blue is for aerialists, etc.). Their battle movements are as sharply-colored and well-choreographed as North Korean political rallies. Of special bravery are blue team commandress Lin Mae (Jing Tian), General Shao (Zhang Hanyu) and Strategist Wang (Andy Lau).

The wall and the warriors protect Song dynasty subjects from the fearsome Tao Tei. From a distance, these beasts resemble dragons but they are not. They are more like larger, angrier iguanas with eyes on their shoulders and relentless murder in their hearts.

Director Zhang Yimou (perhaps best remembered stateside for 2002’s “Hero”) is an action maximalist. “The Great Wall” is written by Tony Gilroy; he adapts a story from Max Brooks, who lifted the sequence from his book “World War Z” in which the zombie horde scales a big wall.

William has reached a mystical level as an archer and earns his keep shooting the reptilian beasts off the battlements. He also proves himself smooth with chopsticks and friendly banter with Lin Mae.

Lin Mae learned English from the other European speaker on the wall, Sir Ballard (Willem Dafoe), who tries to enlist William and Tovar to steal some gunpowder and hightail it back to Europe.

The tough truth about the narrative is that the Tao Tei must eventually get past the barrier to keep the plot moving. But how?

A spoiler alert for those engaged in the quixotic construction of great walls to keep “them” out: They’re going to dig great tunnels. Watch the trailer below:

‘The Great Wall’ is showing at the Sonoma 9 Cinemas. Rated PG-13. Running time 1:46. Visit cinemawest.com.