Mario and Zelda, two of the most successful video games in the world, are completely different from one another - though both are from Nintendo. Mario is a man of action ready to jump on anything that moves in a 2D platform world. And Zelda is a woman of power who has the destiny of the world in her hands.

Neil Armstrong was the first man on the moon. And Elon Musk wants to go one step further and take us to Mars. But they had completely different ideas about how to go about it.

Metallica, the band that pushed the metal to the next level, had a dizzying rise to the top punctuated with tragedy and conflict. But they didn't let that stop them, and they are still going strong today.