1. In the past, toothbrushes had pig hairs for bristles.
2. Builders of Japan's Nijo Castle created squeaky floors to prevent stealthy intruders.
3. Spider silk is used to make fishing nets in some countries.
4. To stay alert for predators, only half a dolphin's brain goes to sleep.
5. The largest known hailstone in the U.S. was about the size of a soccer ball.
6. A river in Canada once turned red.
7. You are more likely to be in a bad mood on Thursdays, according to a recent study.
8. There was a hotel made of garbage in Rome, Italy.
9. Babies' cries can sound different in various languages.
10. A man dressed as Santa Claus went skydiving over the North Pole.
