A bridge with a nervous system.

"Researchers want to build in to bridges, airplanes, and other large structures a type of nervous system that, among other things, would detect any defects such as cracks or rust, and relay that to a central computer that could tell engineers and repair workers what needed to be fixed. This Structural Health Monitoring (SMH) system would use ultrasound waves travelling through really teeny, tiny fibers embedded into the material to detect any potential dangers."