The day after Christmas, 2004, an earthquake sparked a series of massively destructive waves in the Indian Ocean. The tsunami killed 230,000 across the region. Millions more were left homeless.

Thailand was among the tsunami’s targets. Devastating tidal waves crashed upon Thai beach communities in 10-minute intervals, leaving 5,000 dead and more than 2,800 missing.

The factually based The Impossible focuses on a family that plans to spend its Christmas holidays at Thailand’s Orchid Resort. Arriving from Japan on Christmas Eve, the family gets a few brief, fun days on the beach before they, and millions of others, are struck by the tsunami’s epic power.

Working from a story by Maria Belon, the Spanish woman whose family endured the seemingly impossible tale of survival told in The Impossible, Spanish writer-director Juan Antonio Bayona, screenwriter Sergio G. Sánchez, a sprawling cast and what must have been an army of behind-the-scenes crew members, re-create Dec. 26, 2004, in Thailand, and the harrowing days that followed.

The Impossible presents the big picture in panoramic shots of tsunami waves and terrifying images of victims swallowed by, trapped and battered in rivers of rushing, debris-filled water.

Bayona insisted upon using real water to re-create the tsunami and spontaneously generated inland river that engulfs Maria and her oldest son, Lucas. The dirty brown water, such a contrast to the beautifully clear sea that the family had so recently been swimming in, looks angry and vicious.

The director also insisted upon filming at the locations where the story takes place. These include the Orchid Resort.

For the film, the Alvarez Belons, who are Spanish, become a British family. Maria and Henry travel to the Orchid Resort with their three sons, Lucas, Simon and Thomas. Naomi Watts and Ewan McGregor give what likely are the most wrenching and physically demanding performances of their careers. In the tsunami’s wake, their characters are separated from each other and their children.

The family members’ agonizing struggles to find each other in the midst of catastrophe are powerfully dramatized in The Impossible. The story, like the tsunami waters, grabs moviegoers and sweeps them along.

Beyond the grand horror of giant waves and ruined landscapes, the film’s smaller detail, such as the strong breeze that anticipates the tsunami’s first strike and the empathy in a Thai aide worker’s face, enhance the story with an artist’s subtlety.

Despite the film’s focus upon a single British family, Bayona also presents the larger scope of the tragedy. A camera follows one of Henry and Maria’s sons through the inundated halls of a Thai hospital. Another shot pulls away from the hospital grounds, gradually depicting the crowds of survivors there. Difficult to watch but also difficult to turn away from, The Impossible is shattering.