No other country has a greater allegiance to freedom of speech than the United States. "Nowhere is speech more free," said Winston Churchill, the eloquent British prime minister who led his country in World War II. It was Churchill, many recall, who rallied his fellow citizens during the Battle of Britain with the now famous "blood, sweat, and tears" speech. So popular was this phrase, that a 1960s rock group took it as its name. Franklin Roosevelt, the U.S. president during the Great Depression and World War II, posited a world built on four basic freedoms, the first and foremost being the freedom to speak one's mind openly and without fear. Wendell Willkie, who once ran against Roosevelt for president, said that "freedom is an indivisible word" and that "we must be prepared to extend it to everyone."

Alexander the Great died in Babylon on June 10, 323 B.C. A modern town in Suffolk County, Long Island, is named for this ancient Near Eastern city. At the time of his death, the famous Macedonian warrior-king had conquered much of the known world, and his armies had reached as far as India. We are not sure about the cause of Alexander's death. The Roman general Julius Caesar died at an age older than Alexander did. However, we know what killed Caesar: several well-placed knife points in his abdomen. Some historians say Alexander was poisoned; others believe he drank himself to death. However, medical experts, who have read eyewitness accounts of his death, theorize that the culprit was typhus, a disease contracted by ingesting contaminated food and water. Historians who traveled with Alexander say that he suffered severe intestinal distress, that he had a high fever, and that he eventually fell into a coma. These symptoms are consistent with those of typhoid fever. Typhus is treatable with modern medicines. However, many people still suffer from it, especially those in third-world countries, where sewage and water purification systems are often inadequate.

Believe it or not, money as we know it was first used as a medium of exchange about 4,500 years ago. The Mesopotamians were probably the first to create coins by molding silver into large rings, which were exchanged for goods and services. The Mesopotamians built a civilization in the Tigris/Euphrates Valley, in what is now Iraq. Using silver rings made commerce a lot easier than bartering had. In addition, it allowed people to store, transport, and preserve their wealth as well as to pass it on more easily to their descendants. Of course, the modern banking system would have to wait several millennia. Banking was invented by the Florentines during the Italian Renaissance. There is even evidence that as far back as 5,500 years ago, Near Eastern peoples had fashioned tokens out of clay to represent various quantities and types of goods or animals. For example, one token might represent a sheep, another a cask of wine. Native Americans used wampum in an analogous way, but they never developed a cash system like that seen in the Mesopotamians' silver rings.

Le Systeme International d'Unites (SI) was created about 40 years ago to bring some consistency to the process of scientific measurement. It comprises seven major categories of measurement. Canadians and Europeans use the metric system, while Americans and the British use the English system. The principal SI unit for length is the meter. Mass is measured in kilograms, time in seconds, electricity in amperes, temperature in kelvins, the intensity of light in candelas, and atomic weight in moles. The SI also lists several derived units of measurement used for various applications. Among these are the hertz, the joule, the watt, the volt, and the newton, all of which are named for important scientists and inventors. Elements such as fermium, einsteinium, and curium are also named for scientists. However, most elements derive their names from other sources.

Giotto, a 13th-century artist, is considered by many to be the father of modern painting. He was also an architect and made important contributions to the field, serving as chief architect of the cathedral (the duomo) in Florence, Italy. Giotto came on the scene at the beginning of the Renaissance—the "rebirth" of the arts and of learning in Europe. He turned away from the static and remote style of painting reflected in religious art dominated by Byzantine influences, and he endowed his figures—both earthly and heavenly—with recognizable human qualities. His renderings of natural and urban landscapes were also far more realistic than those seen earlier. In addition, he introduced movement and perspective into his works, thereby creating an entirely new way of representing the world. Dante and other Italian poets celebrated Giotto in their writing, and one can still see Giotto's beautiful bell tower standing tall beside the duomo in Florence.