Abandoned along the side of the road, on the steep hillside just outside the small town of Popina, Serbia is a series of sculptures long forgotten to most non-locals, despite being designed by the man behind the most stunning memorials in the Balkans.

Dedicated to the fighters of WWII's Trstenik's NOP Detachment and the troops of the Kraljevačkog Detachment, Popina Memorial Park consists of a series of giant stones – some shaped like pyramids, others like smooth arches – all with holes seemingly blasted through their centers. Standing several stories high, the sculptures themselves dwarf the vehicles necessary to reach the site, and a human can easily pass through their centers fully upright. Scattered along a wooded slope, at a certain angle one can align the voids into a tunnel-like configuration, which eerily leads to nowhere. 

Completed in 1981, the tribute was designed by the famous designer Bogdan Bogdanović. Though his name may not immediately ring a bell, this one man is responsible for some of the most immediately recognizable memorials in Eastern Europe, including Bosnia and Herzegovina's Partisan Memorial Cemetery, the Stone Flower at Jasenovac, Croatia, and Kosovo's Mitrovica Miners Monument, to mention a just few.

Despite being strikingly minimal in its execution, Popina Memorial Park has a way of sticking with its visitors, even if they know nothing of what once transpired here. On October 13, 1941, a small coterie of troops met in one of the first frontal combat engagements against Germany's troops. Heavy casualties were incurred. This forgotten memorial at Popina, which ranks among Bogdanović's forgotten masterpieces, was built to commemorate the losses suffered while defending these hills.