Hello there!
The ring of the Nibelung is an epic opera cycle that when performed completely, last about 15 hours (4 opera nights).
This is an opera composed by Richard Wagner over a period of more than 25 years, based on German mythology. The history is about the fighting between gods, heroes and mythological creatures for the control of a magic ring which gives dominance over the world. It is composed of 4 operas, named The Rhinegold, The Valkyrie, Siegfried, and Twilight of the Gods.
Have a good day!