The Impossible is a gripping drama based on a true story. It also could be considered a horror movie: A family on vacation in Thailand is torn apart during the devastating 2004 tsunami that killed more than 275,000 people. As the mother of three sons, Naomi Watts delivers a mesmerizing, unbearably poignant performance. Injured and separated from her husband (Ewan McGregor) and two of her sons, Maria fights for her life alongside her eldest child (Tom Holland, right). ”Even when she’s dying, she needs to be strong for her son. I can relate to that,” says Watts, 44, who has two sons with Liev Schreiber. ”In the beginning, the idea of making a movie about the tsunami was weird to me,” she says. ”I didn’t want to be in something that glorifies it, given how many lives were lost.” She needn’t have worried. Thanks to Watts’ ability to convey empathy, courage, and heroic motherly love, she’s created a moving tribute to the real-life woman she portrays — and every single soul affected by that horrific natural disaster.