Rādkān

Radkan lies in the Khorasan country northwest of Mashhad. Its best-known monument is a tall brick tower with a conical roof, raised in the thirteenth century during the Ilkhanid period. Thirty-six rounded ribs articulate the outside of the tower, while its interior has eight sides. The building served as a tomb, though its occupant is unknown. Its distinctive form makes it one of Khorasan's notable medieval monuments.