What is the setting of the poem "Ozymandias"?

"Ozymandias" is set in a desert. This setting is an important part of the story Shelley is telling through this sonnet.
A traveller who is traversing the desert comes upon the broken statue of the once mighty Ozymandias. All around is nothing but vast tracts of desert sands, as far as the eye can see. Everything is empty, silent, and desolate.
According to the inscription on the broken statue, however, this area was once the mighty, bustling kingdom that Ozymandias ruled, a place so powerful that Ozymandias advised other rulers to look at it and "despair."
The contrast between the current setting and what Ozymandias's thriving kingdom once was couldn't be more stark. The new, desolate setting is a warning to modern day tyrants that their kingdoms too will come to be nothing.