Global Strange Sounds

What is this?? Nobody can figure it out.
Sure are a whole lot of videos.
Is this a worldwide hoax or something real?

http://youtu.be/GZ2ZcmMxehk

Uploaded by dutchsinse on Jan 16, 2012

Something strange is afoot --- unknown sounds heard globally over the past few days..
basically starting up in rapid pace on January 11, 2012 --- up until today (jan 16 2012).
I don't know how long this will continue, or what it is.

This is the Original video I saw, filmed in Alberta Canada

http://www.youtube.com/watch?v=gtLNmdZTf_g

And this one from Manitoba Canada

http://www.youtube.com/watch?v=xf4e-AxJ7nM

And this one from Poland
which scared the person who sent it to me.

http://www.youtube.com/watch?v=IrqdxGTxeOs&feature=related