The Last Stand
"The Last Stand" is a song by the Swedish metal band Sabaton the titular last stand being of 189 Swiss Guardsmen during the Sack of Rome in 1527 by unpaid landsknecht (mercenaries) in the service of Holy Roman Emperor Charles V. This last stand delayed the mutineers long enough for the Pope to escape to Castel Sant'Angelo.
What does the last stand have to do with the alt-right? Not a damn thing, really. However, Sabaton is notoriously difficult to understand without displayed lyrics due to the heavy guitar and drums, and "The Last Stand" is no exception. As such, the song is often interpreted as a song about the Crusades (due to audible references to the Holy See, and the first line of the chorus, "For the Grace and the Might of our Lord!"), not a song about disgruntled German mercenaries plundering one of Christianity's holiest cities because they weren't being paid. Entire videos are posted playing the song over footage from documentaries about the Crusades, and comments for every video of it on YouTube seem to consist of either people saying "Deus Vult!" (allcaps optional) or the (more likely ignored) people trying to point out what the song is actually about. It also seems to have become one of many theme songs for the alt-right movement.
If you're into metal, it's a damn good song. Just don't scroll down if you value your faith in humanity. Actually, this is generally good advice with regards to Sabaton songs. Which is a shame, really, since a lot of their songs are quite good.