Resteeming this - It's a fascinating building!!!! I read on wiki - It was built on the peak by the Bulgarian communist regime. It commemorated the events of 1891, when a group of socialists led by Dimitar Blagoev assembled secretly in the area to form an organised socialist movement that led to the founding of the Bulgarian Social Democratic Party, a forerunner of the Bulgarian Communist Party.

Have you seen this pop video recorded there in the snow!!