The tombs portrayed in the cover of The Fall of Hyperion, with the Shrike Palace in the back.
"The Time Tombs of Hyperion" by EofAlien on Deviantart.
The Time Tombs are a group of six mysterious structures in a remote valley on the planet Hyperion. Prior to the fall of the Hegemony of Man it was widely believed that the Time Tombs were constructed in the far future and subsequently sent traveling backward in time. Speculation regarding the purpose of the tombs and the reason they were sent traveling backward in time raged until these questions were answered definitively during the Final Shrike Pilgrimage.
The six tombs are: