Stećak.

One more of this ancient tombstones. ( well, it seems a wall...but is a stone)

Stecci: Appearing in the mid 12th century, with the first phase in the 13th century, the custom of cutting and using stećci tombstones reached its peak in the 14th and 15th century, before being discontinued in the very early 16th century during the Ottoman conquest of Bosnia and Herzegovina.[1] They were a common tradition amongst Bosnian, Catholic and Orthodox Church followers alike,[3] and were used by both Slavic and the Vlach populations.[4][5]