Take a listen for a few minutes to this excerpt from Richard Wagner’s creation of 1882.
And this will get you up to speed about the story (or here).
If you go to the 5:00 mark of this video, you can watch some of the Holy Grail scene.
A comment from a German tenor who recently sang the lead role:
“Every time I’m overwhelmed by the beauty of this music… It really pulls you into this world. Even people who are not religious become religious while hearing this music…
“I had people telling me that this opera makes you understand again why you are a Christian, and they were saying that in the audience the person next to them turned round saying ‘it makes me actually very jealous, I wish I were a Christian like you!’ ”