Strange sounds, possibly made by alien life forms or UFOs, are popping up in increasing numbers worldwide.

From Bucharest, Romania to Arvada, Colorado, these booming noises have been heard, taped and uploaded to YourTube for your viewing pleasure. One of the most popular videos is from Conklin, Alberta, Canada where loggers are shown staring up at a blue sky, while a whining metallic sound envelopes them.

Other videos of eerily similar sounds were recorded in Manitoba, Canada and Kota Samarahan, Malaysia. Is it aliens making contact, again?

Otherss (joke) that it's the groaning of the gates of hell in anticipation for the end of the world (if the Mayans are to be believed). Another YouTube commenter joked that the sounds were merely "Chuck Norris snoring." Whatever they are, these sounds have whipped the internet into a tizzy. There's now a whole website dedicated to tracking these strange reverberations in the sky.

Several commenters on YouTube are chalking up the sounds to HAARP, or the High Frequency Active Auroral Research Program. Funded by the U.S. Navy, Air Force and the University of Alaska, HAARP is a common fall guy for mysterious and unexplained events. But so far, this seems unlikely. Cooler heads are reasoning that this is all just a viral marketing scheme by the makers of the video game Half-Life 3… or some company miffed that their sales could get a whole boost from this whole "viral video craze."

Now all we need is for someone to connect the Illuminati to this story. What do you think is causing these mysterious sounds?