Where would you find the world's largest single-aperture optical telescope?

The Gran Telescopio Canarias (GranTeCan or GTC), also known as the Great Canary Telescope is a 10.4 m (410 in) reflecting telescope located at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain.

As of 2015, it is the world's largest single-aperture optical telescope. The distribution of the availability of time to use the telescope meets its financial structure: 90% Spain, 5% Mexico and 5% the University of Florida.

Construction of the telescope, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level, took seven years and cost €130 million (£112 million). Its installation had been hampered by weather conditions and the logistical difficulties of transporting equipment to such a remote location. First light was achieved in 2007 and scientific observations began in 2009.

The GTC Project is a partnership formed by several institutions from Spain and Mexico, the University of Florida, the National Autonomous University of Mexico,[better source needed] and the Instituto de Astrofísica de Canarias (IAC). Planning for the construction of the telescope, which started in 1987, involved more than 1,000 people from 100 companies.