Hyper-realistic cinematic action sequence, 15 seconds, 16:9. An experimental maglev train travels at extraordinary speed along the inside edge of a colossal ringworld. Every kilometer reveals a new landscape without cutting away: towering alpine mountains, endless forests, futuristic cities, vast oceans crossed by kilometer-long bridges, glowing deserts, and giant waterfalls disappearing over the artificial horizon. The camera alternates between low rail tracking, helicopter flybys, cockpit POV, drone pursuit, overhead IMAX shots, and dynamic side-mounted angles as the train leans gracefully through immense curves. Final shot: the train races toward the sunrise while the ringworld arches impossibly across the entire sky. Style: Ultra-realistic IMAX cinematography, physically believable megastructure, cinematic lighting, immense environmental scale, smooth continuous motion.