Alexander Graham Bell

Alexander Graham Bell invented the telephone in 1876 and created the most important communication technology in human history before the internet. His patent — U.S. Patent 174,465 — is considered the most valuable patent ever issued. The Bell Telephone Company became AT&T, which at its peak was the largest corporation in the world and the backbone of American telecommunications for over a century.

Bell's work on the telephone grew from his research into speech and deafness. His mother was deaf, his wife was deaf, and he was a professor of vocal physiology at Boston University. His deep understanding of how sound travels and how the human ear processes it gave him the insight to convert sound waves into electrical signals and back again.

Beyond the telephone, Bell made significant contributions to aviation (he experimented with tetrahedral kites and hydrofoils), worked on early precursors to the metal detector (to find the bullet in President Garfield's body), and founded the National Geographic Society. He was also an early advocate for deaf education, though his views on eugenics are a controversial part of his legacy.