The Gran Telescopio Canarias (GTC, sometimes called GRANTECAN), is a 10.4-m (409-in.) segmented telescope built at the Observatorio del Roque de los Muchachos (ORM), on the island of La Palma in the Canary Islands, Spain. It is considered the largest telescope in the world because of the useful size of its primary mirror. It is also the first segmented telescope built in Europe and is being used as a test bench for the next generation of telescopes, particularly the European Extremely Large Telescope (E-ELT).