Rendering of the ThirtyMeter Telescope from http://www.tmt.org/news-center/new-renderings-reveal-planned-design-tmt
California and Canadian university plans to construct the world's largest telescope, the thirty meter telescope, atop the summit of Mauna Kea, won approval from the Department of Land and Natural Resources on Friday. The decision allows the thirty meter telescope project to negotiate a sublease with the University of Hawaii, which leases the land from the State of Hawaii.
Construction costs for the project are estimated at $1 billion. When constructed, the telescope will be able to monitor planets circling stars other than the sun. More information on the project is here.
