Take a long enough time-scale and you could argue that everything is temporary. There’s all the difference in the world, in terms of longevity, between the Great Pyramid and a Higgs boson, however.
At the shorter end of the time frame there are, most obviously, fireworks and flowers.
So here are two images that illustrate the temporary life-cycle of a flower, from our garden earlier this year:
Sic transit gloria mundi.