Nina investigates how roads are made - with the help of Luke, her sight neuron. Engineers Isla and Mia visit Nina in her workshop and discover that rocks are good for making roads because cars and bikes don't sink. They visit some roadworks and see that roads have layers of big and small rocks and underneath roads are lots of pipes carrying things to people's homes.

Originally released by BBC Worldwide Learning, 2013. Streaming video file encoded with permission for digital streaming by Infobase on April 29, 2015.