"Ozymandias" is presented as the narrator telling the report of "a traveller" about a sight seen on his travels.
Partially covered by the desert sand, there are "two vast and trunkless legs of stone" - the only remains still standing in their original situation. Near the leg stumps lie "a shatter'd visage" - the broken but recognizable head and face from the statue. The skill of the sculptor is still evident, even when it is broken and weathered. The face's "frown and wrinkled lip and sneer of cold command tell that its sculptor well those passions read" - the person portrayed by the statue looked down upon those around him and demanded respect and obedience.
The statue's base has inscribed upon it words spoken by the subject of the statue, announcing his name and proclaiming the overwhelming magnificence of his power and accomplishments. "My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!" However, there isn't anything else left of the statue - it is broken to pieces, blown away or engulfed by the desert sands.
The poem points out the impermanence of life, fame, and accomplishments. Ozymandias, who considered himself invincible, is now broken and buried in the desert. The poem warns those who think themselves all-powerful that they will, in the future, be forgotten and overshadowed.
The poem's theme could apply to rulers and to any others who think their efforts will last forever. Human activities are inevitably going to be lost as time goes on.