Where do most tigers live?

India? Southeast Asia? Nope... the good ol' United States. A century ago, there were more than 40,000 tigers in India, today there are between 3,000 and 4,700. Yet, there are more than 4,000 tigers living in captivity in Texas alone. In fact, the American Zoo and Aquarium Association estimates there's around 12,000 tigers in private captivity in the United States. Mike Tyson owns four of them.

What was the first invention to break the sound barrier?

You're probably imagining Chuck Yeager strapped to the back of the X-1 traveling past 742 mph. But it is actually a whip that first broke the sound barrier. The "crack" of a whip is the loop traveling down the length of the tube as the leather tapers, finally reaching over ten times its original speed. High-speed photography reveals that the crack is when the loop breaks the sound barrier creating a small sonic-boom.

How many senses do humans have?

At least nine. Sure you've got your sight, hearing, taste, smell, and touch. But there are four others that are commonly agreed to be senses.

• Thermoception, the sense of heat (or absence of) on our skin.
• Equilibrioception, the sense of balance.
• Nociception, the perception of pain from the skin, joints and body organs.
• Proprioception, body awareness. This is the unconscious knowledge of where our body parts are without being able to see or feel them.

What is the single largest man-made structure on Earth?

It's not the Great Wall of China or the Great Pyramid. It's actually Fresh Kills landfill on Staten Island, just south of Manhattan. No longer in use, had Fresh Kills continued to operate as planned, it would have been the highest point on the Eastern Seaboard.

What is the best floor of a building to throw a cat from?

Any of them above the seventh floor. Anything higher than the seventh floor and it doesn't really matter ... as long as its oxygen holds out. Cats, like other small animals, have non-fatal terminal velocity. Once they relax (if they relax) they spread themselves out and parachute to Earth like a squirrel. Still, I wouldn't try this at home.