The Thirty-Metre Telescope will finally end in Hawaii, not Chile. When it's finished in 2018, it will be nine times larger than any telescope today.
The 30-meter (98.4-foot) mirror will be composed of 492 segments and, according to the experts, it is destined to dwarf Hubble in many regards. When it's finalised nine years from now, it will be the largest telescope in the world. At least until the 42-metre European Extremely Large Telescope comes online.