Morse code is a communication system that represents letters and numbers as patterns of short and long signals. Invented in the 1830s by Samuel Morse for use with the telegraph, it transforms the alphabet into dots (short signals) and dashes (long signals). The letter E is just a single dot, while the letter O is three dashes. The most famous Morse code signal is SOS (dot-dot-dot, dash-dash-dash, dot-dot-dot), the international distress call.

Before telephones, Morse code allowed people to send messages across vast distances almost instantly by tapping electrical signals through wires. Telegraph operators became skilled at tapping out messages at remarkable speeds, listening to the clicks and translating them back into words. Ships at sea used Morse code with flashing lights to communicate when radio systems failed.

Though modern technology has made Morse code largely obsolete for everyday communication, pilots and ham radio operators still learn it. Morse code proves that you don't need complex technology to send sophisticated messages: just two simple signals, carefully arranged, can convey any thought across enormous distances. Some people even learn Morse code as a mental challenge or a way to send secret messages, tapping rhythms on a table that only other trained listeners can understand.