When it comes to astronomy, size is everything. The biggest telescope on the planet is the 11-metre Hobby-Eberly on Mount Fowlkes in Texas. And the twin 10-metre Keck telescopes perched atop Mauna Kea on the Big Island of Hawaii can work in tandem to act as an even larger telescope. But there are new observatories in the works, with telescopes that will be 30-metres across and larger. Once these turn their gaze into the heavens, astronomers will have some amazingly powerful tools at their disposal.