In 2010 the Colombian army used Morse code hidden in a song to reach soldiers who were kidnapped by FARC guerrillas. It took a while to compose the song in such a way that only people proficient in CW would be able to pick it up from the background music, but eventually they succeeded to compose and send the following message:
A team began experimenting with Morse code using various percussion instruments and a keyboard. They learned that operators skilled in Morse code can often read the signals at a rate of 40 words per minute — but played that fast, the beat would sound like a European Dance track. “We discovered the magic number was 20,” says Portela. “You can fit approximately 20 Morse code words into a piece of music the length of a chorus, and it sounds okay.” The song was called “Better Days”.