Monument in Gonbad-e Kavus
A Unesco World Heritage site since 2012, this 53m tower in Gonbad's center looks like a buttressed-brick spaceship with the cross-section of a 10-pointed star. Built in 1006, it's so remarkably well preserved that one can scarcely believe it’s a hundred years old, let alone over a thousand. You can listen to echoes in the bare interior and, even more spookily, from the marked circular spot some 40 paces in front of the tower.
It was created for poet-artist-prince Qabus ibn Vashmgir (Kavus), the Zeyarid ruler of surrounding Tabarestan who was assassinated just six years after the tower was completed. His glass coffin originally hung from the tower’s dome, but it vanished long ago.