1390s to 1468 Before Johann Gutenberg's invention of movable-type printing, books and other written documents are so rare that reading is mainly a luxury. A native of Mainz, Germany, Gutenberg works for many years to develop a refined technique to replace hand-written and inefficiently printed documents. He restructures the printing process, developing improvements in all aspects of the craft. In 1455 the Gutenberg Bible is published.

1452 to 1519 Leonardo da Vinci is the original "Renaissance Man." Born in a small village in Tuscany, Italy, he eventually becomes a master of several disciplines. Perhaps best known for his paintings and frescoes, he is also deeply involved in the natural sciences, mathematics, and in urban and military design. In 1510, da Vinci designs the horizontal water wheel.

1564 to 1642 While papal belief holds the Earth was at the universe's center, Galileo Galilei's telescope experiments in Italy lead him to conclude the Earth circled the sun. After the Dutch invent the telescope in 1600, he builds an astronomical one eight years later. When the church threatened torture unless he recanted, Galileo did, but said, "nevertheless it does move."

1706 to 1790 Among those in Philadelphia in 1776 declaring independence from England, Benjamin Franklin is a renowned journalist, philosopher and scientist, whose inventions ranged from bifocals to a fireplace known as the Franklin stove. In his famed kite experiment, Franklin proves that lightning is a form of electricity, and that led to his invention of the lightning rod.

1760 John Spilsbury, a London mapmaker, creates the first jigsaw puzzle. His puzzles are made of wood and are hand painted. The idea: to teach children geography.

1857 The first passenger elevator goes into operation, in New York City in 1857. It is constructed by Elisha Graves Otis. The company he started, Otis Brothers, still manufactures elevators. In 1878, the company built the first hydraulic passenger elevator.

1876 Alexander Graham Bell demonstrates communication over a distance via electricity.

1878 German chemist Felix Hoffman, trying to relieve his father's arthritis, came up with acetylsalicylic acid, also known as aspirin. A French chemist had actually made the discovery 41 years earlier, but hadn't realized its true significance.

1879 The lighting of Thomas Edison's carbon filament lamp on Oct. 21, 1879, comes after Joseph Wilson Swan's experiments from 1848 to 1878. Edison, though, knows how to capture the spotlight: He illuminates a street in Menlo Park, N.J. The two collaborate, forming the Edison and Swan United Electric Light Co. Ltd. Walter Cronkite recounts Edison's many inventions.

1892 Coca Cola is invented by John Pemberton. It is sold as a tonic. In 1892 Asa D. Chandler buys the formula and adds carbonated water. This mixture is a hit.

1893 Whitcomb Judson files a patent in 1893 for a slide fastener, an early form of the zipper.

1895 In 1895, British-Italian Guglielmo Marconi develops a means of sending messages without wires, giving rise to the radio. The critical test: when he could hear a gun shot not in view.

1903 Orville Wright controls the "Wright Flyer" accompanied by his brother Wilbur Wright during the first ever controlled and sustained flight at Kitty Hawk, N.C., on Dec. 17, 1903. Made of wood, wire and cloth by the two bicycle mechanics, the plane remains aloft for 12 seconds and travels 120 feet.

1927 Charles Lindbergh completes the first nonstop transatlantic flight in the Spirit of Saint Louis, a monoplane. Lindbergh flies from New York to Paris in 33.5 hours May 20 to May 21, 1927, and becomes a folk hero on both sides of the Atlantic. Walter Cronkite reports on the famous flight.

1939 First introduced at a world's fair in 1939, television was received with mixed reviews. Kids gather around this set in 1954. By 1955, 64 percent of American households owned a television set in 1955, compared to a mere 2 percent in 1949. Television, like the century's earlier invention, radio, revolutionized mass communication.

1945 Smoke billows 20,000 feet above Hiroshima, Japan, after the first atomic bomb strike by Americans on Aug. 6, 1945. The blast kills about 70,000, with thousands later dying of the effects of radiation. Walter Cronkite describes the Hiroshima bombing.

1948 First started in 1948, Tupperware home demos are so effective at communicating the benefits of the plastic storage containers' tight seal that by 1951 all Tupperware products are taken off of store shelves to be distributed in this manner. This gathering of women took place in 1958.

1950s At at time when typewriters still reigned supreme in offices, one artist-turned-secretary is attuned to those who err. Bette Nesmith Graham knows that in the art world, gesso can disguise errors. She whips up a like solution at home and sells it on her own when IBM turned her down. The Gillette Co. buys the Liquid Paper Corp. for more than $47 million in 1979. (Her son, Michael Nesmith, was a member of The Monkees.)

1955 Zenith engineer Dr. Robert Adler begins designing the first ultrasonic remote control device. It goes into production the next year. The device, known as the "Zenith Space Command," communicates with the television by high frequency sound, ultrasonic waves.

1957 With the launch of Sputnik I, the first satellite sent into space, the Soviets begin a space race with America. Just shy of 2 feet and about 184 pounds, it circles the Earth every 96 minutes. Cronkite describes Sputnik.