Scrapheap Challenge is an engineering game show produced by RDF Media and broadcast on Channel 4 in the United Kingdom. In the show, teams of contestants had 10 hours in which to build a working machine that could do a specific task, using materials available in a scrapheap. The format was exported to the United States, where it was known as Junkyard Wars. The US show was also produced by RDF Media, and was originally shown on The Learning Channel. Repeats have aired on another Discovery network, the Science Channel..