Should you hunt tigers at night?

Due to a retinal adaptation that reflects light back to the retina, the night vision of tigers is six times better than that of humans.



What makes a penguin so special?

The penguin is the only bird that can swim, but not fly. It is also the only bird that walks upright.



-- June 13

1983: The U.S. space probe Pioneer 10 became the first spacecraft to leave the solar system as it crossed the orbit of Neptune. AP Photo/NASA (13K)

1971: The New York Times began publishing the "Pentagon Papers," a secret study of America's involvement in Vietnam.




When was helium discovered?

During an eclipse of the sun in 1868, spectral lines were located that were attributed to an unknown element that was called "helium," from the Greek word for "sun." Thirty years later, helium was discovered on Earth.


How is a penny different from other coins?

Other than its color, the Penny is the only coin currently minted in the United States with a profile that faces to the right. All other coins the silver dollar, half dollar, quarter, dime, and nickel all feature profiles that face to the left.


Why shouldn't you yell "Fire!" at a movie house?

Someone maliciously shouted "Fire!" at a copper miners' Christmas party in Calumet, Michigan in 1913. Panic ensued and 72 lives -- mostly children's -- were lost.