We're one step closer to officially living in a new geologic interval, the Anthropocene — the age of humans. A working group of scientists recommended the planet's next chapter start in the 1950s, when people began making significant, lasting alterations to the environment. Yes, the earth is the Roman Colosseum, and humanity's the guy who carved his name into it.

Other stuff also happened ... a NATO summit, big-name retirements, angst over a movie about dolls. How well have you been paying attention?