Step 1 : Introduction to the question "What is the world's best-selling musical instrument?"
The harmonica is the world’s best-selling musical instrument. Harmonicas originated in the early 1800s in Europe. They gained popularity in the 1920s in the U.S. and were used in blues recordings. Christian Friedrich Ludwig Buschmann is often cited as the inventor of the harmonica in 1821, but other inventors developed similar instruments at the same time. Clock maker Matthias Hohner began crafting harmonicas in 1857 and soon owned the largest harmonica factory in the world. By 1986 the harmonica maker Hohner had produced 1 billion harmonicas.