The Ruins, by Scott SmithRead about the other entries on the list.
Four fresh-faced, semi-Ugly Americans and one German are vacationing in Mexico when they decide to ditch the beach and check out an off-map archaeological site. Once there, they are surrounded and trapped by frantic locals who draw weapons as soon as one of them fatefully steps into the vines at the edge of the ancient ruins. Unable to leave the site, and at the mercy of sinister forces, our heroes turn into a bickering, hysteria-fueled mess. Written with a sense of terrifyingly plausible, slow-motion, “this can’t be happening” dread that paralyzes the reader, the horror stems from what the main characters do to each other to stay alive amid a psychologically torturous situation.