Contrary to their hilarious claim to have written the Greatest Song in the World (actually called "Tribute"), that honour does not belong to Tenacious D (Jack Black and Kyle Gass). TBH the Greatest Song in the World is a lot of fun and worth having a peek at and especially with the accompanying video which also features Dave Grohl and Ben Stiller.

Funnily enough it does belong (at least in part to one of Jack Black's all time heroes - Ronnie James Dio, when he was in Rainbow. The truly stupendous second album Rainbow Rising, reached heights never achieved before - or since - with the epic that is Stargazer.
Spanning three verses, with repeat choruses, the soaring solo by Ritchie Blackmore and the stunning outro with a message of hope the song is complete in its perfection.
Telling the story of a wizard who aspires to build a tower to the sky to show that he can fly he has the hubris of a man who would be God and in making the song about this it has a strong resonance with the Biblical Tower of Babel, in which man tried to ascend to the stars to be like God. To build his tower the wizard has a vast number of slaves who toil "in the wind and rain, with whips and chains" to make his dream reality. Despite the reference to rain, the general environment is dry and hot - "hot wind moving fast across the desert". After nearly a decade of inhumane treatment the tower is ready and after the guitar solo in the third verse the wizard ascends to fulfill his dream to fly to the stars. Instead, he plummets to the ground and "there's blood on the sand" and at that point the slaves are free and the lengthy outro captures their mood...
...which incidentally is also wonderfully expounded upon in the very next song on the album - "A Light in the Black", which is a natural and perfect follow on from Stargazer...
"my eyes are bleeding", "my heart is leaving", "I'm coming home.' and best of all "Now, look, look, look, look, look at his tower of stone... I see a rainbow rising, look there, on the horizon." In invoking the rainbow rising. the song once again draws on Biblical symbology and the promise of hope delivered after Noah's Flood.
I am not being religious here, whatever your views, this is what the Bible represents in terms of the symbology - belief and faith are another matter altogether.
Then finally with hope in their hearts and the constant repetition of "coming home," there is a real sense of completion of hope fulfilled and tyranny overcome.
Sadly, there is no live performance of the late Ronnie James Dio performing this song (there is a kind of mocked up one in which the elements kind of work but it is obvious that it is many different cuts that have been spliced together). So here I give you the studio version (just as I did yesterday) -
Alternatively (or additionally), check out this live performance from 2016 performed by a different incarnation of Rainbow, but still featuring Ritchie Blackmore on guitar and the excellent Ronnie Romero on vocals. He had a hard act to follow - literally nobody could follow the late great Ronnie James Dio - but this is as good as it could ever be and it is LIVE and the backing singers just take it to the stratosphere.
Hope you enjoyed.
As always stay safe and well my friends.