They call it “the hum.” Apparently people all over the world are (and have been since the 1800’s) reporting a low-frequency noise that seems to emanate from the sky seemingly from no visible source.

The phenomenon is reported here on io9.

From the story: What exactly are we hearing in these YouTube videos posted by people who claim they’ve recorded ear-splitting roars coming from the sky with no explanation? Here you can see one of the latest, recorded in Budapest, Hungary last week. Conspiracy-lovers are calling them “apocalyptic sounds.” Whatever they really are, they’re freaking creepy. Are they jet engines attached to UFOs, bizarro weather, or pure fakery?

-Annalee Newitz, io9.com

The sounds have been reported in Arizona US, New Zealand, Costa Rica, Alberta Canada, Budapest, The United Kingdom and others. What’s going on? Is it a worldwide hoax? A sign of the Apocalypse? An unknown weather phenomenon?

The story was also reported on The Truth Behind The Scenes blog and here’s a link to a blog that exists solely to document the phenomenon: Roaring Sky Blog.

I leave you with this:

Also this: