The famous words of Alexander Graham Bell have given many people hope in the face of disappointment: “When one door closes another door opens. But we so often look so long and so regretfully upon the closed door, that we do not see the ones which open for us.”

Bell tried many doors as he attempted to invent a device that could transmit a human request. After countless experiments, while working on his invention one day, Bell called out to his assistant in the next room: “Mr. Watson, come here.” To their surprise, Watson heard Bell’s request over a transmitter they’d been working on. These turned out to be the first words ever heard over a telephone.

When Thomas Alva Edison gave his famous quote, “Genius is one percent inspiration and ninety-nine percent perspiration,” he really meant it! He was always a hard worker. As a child, Edison read nearly every book in the public library. When he was only twelve, he sold snacks on trains and had another business selling vegetables. When he was thirteen, he started his own newspaper, and at fifteen he became an expert telegraph operator.

In his spare time, Edison worked on inventions. Early on, a blow to his ear and a case of scarlet fever damaged his hearing. The silence of his deafness only helped him concentrate. Eventually Edison opened a laboratory in Menlo Park, New Jersey. There he invented the first incandescent electric lightbulb and the first phonograph, or record player. A few years later, he created the first silent motion pictures. By the end of his career, Edison had patents for over 1,000 inventions. When he died in 1931, households all over America dimmed their electric lights to honor him.

By the time Louis Pasteur stated that “chance favors the prepared mind,” he had learned a lot about being well prepared. As a medical researcher in Paris, Pasteur studied microbes for many years. He hoped to understand how germs and infectious diseases were related. Pasteur’s hard work led to the “germ theory” in medicine. He developed a life-saving vaccine to fight rabies, and he created a process called “pasteurization” that uses heat to kill germs in food. Today the Pasteur Institute in Paris is still a very important medical research center that helps prevent and treat deadly diseases.

The French engineer Gustave Eiffel gave much credit for his success to his parents. He said, “From my father I inherited a taste for adventure, from my mother a love of work and responsibility.” Eiffel had many great adventures in his career. Using the new technology of building with iron, he designed innovative bridges and viaducts. He even helped design the Statue of Liberty for New York City. But his most amazing feat was the Eiffel Tower in Paris, the tallest structure in the world until 1930.

Eiffel faced a lot of resistance to building the tower. At first, many people thought the design was terribly ugly; others were sure the tower would topple over in strong winds. But Eiffel had designed his tower so that the wind could blow safely through its open latticework. In time it became the most beloved symbol of Paris. Today the Eiffel Tower has over 6 million visitors a year.

Thomas Alva Edison actually met with Gustave Eiffel in Eiffel’s tower office during the 1889 Paris World’s Fair. Also on his visit to Paris, Edison met with Louis Pasteur at the Pasteur Institute. The only one of the four great men not in Paris that summer was Alexander Graham Bell, but a display of his new telephone invention was one of the most popular exhibits at the World’s Fair.