Historical cemetery of Khaled Nabi

This cemetery is north of Iran, in outlying and impossible
highlands at 90 kilometers from Gonbad-e Kavous. 
As recent census from
tombstones of this cemetery, there are almost 600 tombstones shaped of male
genital and female chest. 
Sometimes this plain called genital plain. Although,
as observers enumeration, now just remain half of this tombstones. 
As one research and estimation that did about this
cemetery, maybe the older grave has almost 1000 years old that is belongs to
Islamic and Seljuk period. The newest of them is belongs to 70 years ago that has
a date on it.