Astronauts can't belch - there is no gravity to separate liquid from gas in their stomachs.Ancient Roman, Chinese and German societies often used urine as mouthwash.The Mona Lisa has no eyebrows. In the Renaissance era, it was fashion to shave them off!Because of the speed at which Earth moves around the Sun, it is impossible for a solar eclipse to last more than 7 minutes and 58 seconds.The night of January 20 is "Saint Agnes's Eve", which is regarded as a time when a young woman dreams of her future husband.It takes glass one million years to decompose, which means it never wears out and can be recycled an infinite amount of times!Gold is the only metal that doesn't rust, even if it's buried in the ground for thousands of years .Your tongue is the only muscle in your body that is attached at only one end .If you stop getting thirsty, you need to drink more water. When a human body is dehydrated, its thirst mechanism shuts off.Each year 2,000,000 smokers either quit smoking or die of tobacco-related diseases.Zero is the only number that cannot be represented by Roman numeralsKites were used in the American Civil War to deliver letters and newspapers.The song, Auld Lang Syne, is sung at the stroke of midnight in almost every English-speaking country in the world to bring in the new year.Drinking water after eating reduces the acid in your mouth by 61 percentPeanut oil is used for cooking in submarines because it doesn't smoke unless it's heated above 450?FThe roar that we hear when we place a seashell next to our ear is not the ocean, but rather the sound of blood surging through the veins in the ear.Nine out of every 10 living things live in the oceanThe banana cannot reproduce itself. It can be propagated only by the hand of manAirports at higher altitudes require a longer airstrip due to lower air densityThe University of Alaska spans four time zonesThe tooth is the only part of the human body that cannot heal itself.In ancient Greece , tossing an apple to a girl was a traditional proposal of marriage. Catching it meant she accepted.Warner Communications paid $28 million for the copyright to the song Happy Birthday.Intelligent people have more zinc and copper in their hair.A comet's tail always points away from the sunThe Swine Flu vaccine in 1976 caused more death and illness than the disease it was intended to preventCaffeine increases the power of aspirin and other painkillers, that is why it is found in some medicines.The military salute is a motion that evolved from medieval times, when knights in armor raised their visors to reveal their identity.If you get into the bottom of a well or a tall chimney and look up, you can see stars, even in the middle of the day.When a person dies, hearing is the last sense to go. The first sense lost is sightIn ancient times strangers shook hands to show that they were unarmedStrawberries are the only fruits whose seeds grow on the outsideAvocados have the highest calories of any fruit at 167 calories per hundred gramsThe moon moves about two inches away from the Earth each yearThe Earth gets 100 tons heavier every day due to falling space dustDue to earth's gravity it is impossible for mountains to be higher than 15,000 metersMickey Mouse is known as "Topolino" in ItalySoldiers do not march in step when going across bridges because they could set up a vibration which could be sufficient to knock the bridge downEverything weighs one percent less at the equatorFor every extra kilogram carried on a space flight, 530 kg of excess fuel are needed at lift-offThe letter J does not appear anywhere on the periodic table of the elements.And last but not least:In 2012, December has 5 Mondays, 5 Saturdays, and 5 Sundays. This apparently happens once every 823 years!