Watch Modern Marvels Season 18 Online

Don't look now–but there's a lot more to your walls than you'd ever imagine. Take a penetrating look inside something we consider utterly mundane, and uncover a surprising and sometimes shocking world. A computer-managed home in Colorado showcases the high tech gadgetry destined to inhabit every wall in the future. At the headquarters of Orkin in Atlanta, a network of walls with cutouts and Plexiglas windows reveal how pests and creepy crawlies of all kinds can congregate in huge numbers inside our homes. In Washington, scientists at Underwriters Labs play with fire in the name of research, investigating how our walls can keep us safe–or expose us to a fiery death. And in Los Angeles, a security company demonstrates innovative new technology that can "see" through walls–detecting motion, heat, breathing, even heartbeats.