What is "mramorje"

Mramorje or Bagruša is a medieval necropolis, located in Perućac, Serbia, and is among the best preserved necropoli of the region. The necropolis was built in the 14th century, and extends between the Drina river and the main road that follows its course, at the entrance of the settlement. The site is protected by the Republic of Serbia, as a Monument of Culture of Exceptional Importance, but is nevertheless threatened by the Drina river on one side and the continued expanding of the town of Perućac, on the other. Stećaks was inscribed as a UNESCO World Heritage Site in 2016, of which 3 sites are located in Serbia, Mramorje being one of them.