In celebration of our 5th anniversary, this month we're publishing a series of interviews with innovative leaders about what the next five years hold. To read more about this series, read our editor Nilay Patel's introduction here. Few subsidiaries at Alphabet Inc. inspire as much curiosity as Google X, now called simply "X." X is the company's innovation lab, where ambitious but far-fetched tech ideas are pitched, tested, and either come to life or are ultimately killed. It's where Google's self-driving car concept was developed, where giant internet access balloons were conceived, where glucose-monitoring contact lenses were first experimented with, and where burrito-delivering drones are part of a beta test for bigger things. And while more than 250 employees are behind these far-fetched projects, for the past five years the face of X has been Astro Teller, the so-called "Captain of Moonshots."