"Before me, a message took days to cross a country. After me, a voice could travel in an instant. I was invented in 1876 and within a century I was in every home. What am I?"

Answer: The Telephone. The telephone was patented by Alexander Graham Bell in 1876. Before its invention, long-distance communication required days or weeks via letter or telegram. Within 100 years, telephones were standard in homes across the developed world.