The Gran Telescopio Canarias (GTC or GRANTECAN) is the largest optical-IR telescope in operation. It is located in the northern hemisphere in one of the best astronomical sites worldwide: the Observatorio del Roque de los Muchachos in La Palma, Canary Islands, Spain. GTC is a Spanish initiative led by the Instituto de Astrofísica de Canarias (IAC) and is funded by the Central Government of Spain and the Local Government of the Canary Islands. The main astronomical institutions in Mexico and the University of Florida joined later as international partners. The GTC construction started in 2000 with its ground-breaking ceremony. Technical first light occurred in mid-2007 and regular operations started on March 2009 (Day One). Since then, observing time at the GTC is routinely offered to its international user community on a semester basis. The GTC is one of the Unique Scientific and Technical Infrastructures (ICTS) of Spain.