What does it feel like to be invisible? Who owns the air? How will the universe end? What's the most valuable part of the human body? Most importantly: Could a koala frame you for a crime?

This month's mental_floss (on newsstands now) answers all these burning questions and more! Plus: learn how a bar fight instigated the world's first heart surgery, the true story behind Madeline L'Engle's masterpiece A Wrinkle in Time and how to make a world record–breaking paper airplane. (Not to mention, parenting tips from Bill Murray.)

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