Morse Code

Dot-and-dash code invented by Samuel Morse in 1837. Adopted as the international standard for telegraph and wireless communication, it was the backbone of military and diplomatic communications through two world wars and the Cold War. "SOS (···---···)" was adopted in 1908 as the world's first international distress signal. Still used in amateur radio (HAM), aviation, and maritime contexts in the internet age, and designated a "cultural heritage" by the International Telecommunication Union in 2015.