I wasn't aware that Shelley's poem was written in competition with his pal Horace Smith. I've found his sonnet in Wikipedia. It is thought that they wrote the poems because it was at about that time that another statue of Rameses was discovered and brought to London - almost exactly 200 years ago. The trouble is that in another 200 years much of London will be under water and there probably will never be another civilisation to come there to examine its archaeology.
In Egypt's sandy silence, all alone,
Stands a gigantic Leg, which far off throws
The only shadow that the Desert knows:—
"I am great OZYMANDIAS," saith the stone,
"The King of Kings; this mighty City shows
"The wonders of my hand."— The City's gone,—
Nought but the Leg remaining to disclose
The site of this forgotten Babylon.
We wonder,—and some Hunter may express
Wonder like ours, when thro' the wilderness
Where London stood, holding the Wolf in chace,
He meets some fragment huge, and stops to guess
What powerful but unrecorded race
Once dwelt in that annihilated place.
