For hundreds of years, composers have been using a specific four-note melody to evoke death. It's appeared in dozens of famous movies, and you probably never even realized it. But once you hear it, you'll start noticing it everywhere. Featuring musicologist Alex Ludwig and Strong Songs Host Kirk Hamilton.

Twenty Thousand Hertz is produced out of the studios of Defacto Sound and hosted by Dallas Taylor. Follow the show on Twitter, Facebook, & Reddit.Become a monthly contributor at 20k.org/donate. If you know what this week's mystery sound is, tell us at mystery.20k.org. Discover more at lexus.com/curiosity.Check out Alex’s list of Dies Irae examples at alexludwig.net.Subscribe to Strong Songs where ever you get your podcasts. Check out The Graduale Project’s Youtube page for more Latin chants. Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/diesiraeLearn more about your ad choices. Visit megaphone.fm/adchoices