There is no evidence that iron maidens were invented in the Middle Ages or even used for torture, despite being shown so in some media, but instead were pieced together in the 18th century from several artifacts found in museums in order to create spectacular objects intended for (commercial) exhibition.
Christopher Columbus's efforts to obtain support for his voyages were not hampered by a European belief in a flat Earth. Sailors and navigators of the time knew that the Earth was spherical, but (correctly) disagreed with Columbus's estimate of the distance to India, which was approximately one-sixth of the actual distance.
Marie Antoinette did not actually use the phrase "let them eat cake" when she heard that the French peasantry was starving due to a dearth of bread. The phrase was first published in Rousseau's Confessions when Marie was only 10 years old and most scholars believe that Rousseau coined it himself, or that it was said by Maria-Theresa, the wife of Louis XIV.
George Washington did not have wooden teeth. According to a study of Washington's four known dentures by a forensic anthropologist from the University of Pittsburgh (in collaboration with the National Museum of Dentistry, itself associated with the Smithsonian Museum), the dentures were made of gold, hippopotamus ivory, lead, and human and animal teeth (including horse and donkey teeth).
The signing of the Declaration of Independence did not occur on July 4, 1776. The final language of the document was approved by the Second Continental Congress on that date, it was printed and distributed on July 4 and 5, but the actual signing occurred on August 2, 1776.
John F. Kennedy's words "Ich bin ein Berliner" are standard German for "I am a Berliner". An urban legend has it that due to his use of the indefinite article ein, Berliner is translated as jam doughnut, and that the population of Berlin was amused by the supposed mistake. The word Berliner is not commonly used in Berlin to refer to the Berliner Pfannkuchen.
Entrapment law in the United States does not require police officers to identify themselves as police in the case of a sting or other undercover work. The law is specifically concerned with enticing people to commit crimes they would not have considered in the normal course of events.
Mussels that do not open when cooked may still be fully cooked and safe to eat.
Microwave ovens do not cook food from the inside out. Microwave radiation penetrates food and causes direct heating only a short distance from the surface.
Placing metal inside a microwave oven does not damage the oven's electronics. There are, however, other safety-related issues: electrical arcing may occur on pieces of metal not designed for use in a microwave oven, and metal objects may become hot enough to damage food, skin, or the interior of the microwave oven.
It is commonly claimed that the Great Wall of China is the only man-made object visible from the Moon. This is false.
The notion that goldfish have a memory of only three seconds is false.
Lemmings do not engage in mass suicidal dives off cliffs when migrating. They will, however, occasionally unintentionally fall off cliffs when venturing into unknown territory, with no knowledge of the boundaries of the environment. The misconception is due largely to the Disney film White Wilderness, which shot many of the migration scenes (also staged by using multiple shots of different groups of lemmings) on a large, snow-covered turntable in a studio. Photographers later pushed the lemmings off a cliff.
Bats are not blind. While most bat species do use echolocation to augment their vision, all bat species have eyes and are capable of sight.
According to urban myth, the daddy longlegs spider (Pholcus phalangioides) is the most venomous spider in the world, but the shape of their mandibles leaves them unable to bite humans, rendering them harmless to our species. In reality, they can indeed pierce human skin, though the tiny amount of venom they carry causes only a mild burning sensation for a few seconds.