You and your team of scientists are trapped on Mars. Can you figure out how to survive on the desert planet? -- Today is the anniversary of the best-worst day of your life. The best part was discovering a subterranean city on Mars. The worst part was when you lost contact with Earth. You and ...

View full lesson: http://ed.ted.com/lessons/can-you-solve-the-prisoner-hat-riddle-alex-gendler Want more? Try the buried treasure riddle: https://www.youtube.com/watch?v=tCeklW2e6_E You and nine other individuals have been captured by super-intelligent alien overlords. The aliens think humans ...