The Navy's X-47B autonomous drone reached a major milestone when it flew in 2011, and then last week when it took off and landed from a U.S. aircraft carrier.

It's impossible to overestimate the impact this aircraft will have on drone use, its ethics, and the future of manned fighters.

But what is the X-47B and why is it so earth-shattering? Here's a rundown on the bird and some shots of its groundbreaking achievement.