The theme is the implication revealed or aimed at within the plot of some story. Many a times theme is said to be the message conveyed by different write-ups. Hidden morals are the output of any theme utilized in a plot. Writers use a main idea, said to be the theme, to create content in regards to multiple aspects of life.
Some of the everlasting themes, that I think would never degrade and remain timeless are stated below:
- Materialism
- Individuality
- Dejection
- Hope
- Ethics
- Nature
- Violence; and more.
However, one theme is asked here. So, I would say, "the theme of nature" is everlasting.