So you're probably wondering why I'm mentioning Italian instead of Russian. Well, this Russian Chorus sings amazingly low, at a level called Basso Profondo, which actually means "low bass". It is as deep as a man's voice can get, a little over two octaves below middle C (eighteen keys down to be exact).
Just listen for yourself: the man singing sound like he's trying to call Satan from the threshold of hell.
However, he doesn't actually start until 25 seconds in, so until then you get to see varying pictures of Russian saints, churches, and other religious things.