Knives, shadows, confined spaces, woods, and cities are common iconography in thriller genre films. Knives symbolize violence and death and are used to increase tension. Shadows and silhouettes build mystery and suspense by implying someone is being watched. Being trapped in confined spaces causes characters to feel anxious and struggle to escape. Woods isolate characters and make them feel lost and vulnerable. Cities ground psychological thrillers in reality and bring the drama closer to home for audiences.