These spheres are composed primarily of sandstone and minerals that crystallized during intense geological processes.
Similar stone spheres have been documented in Costa Rica and Mexico, making the Zavidovići site a rare European counterpart.
Some of the largest spheres at this location weigh several tons, requiring heavy machinery for any potential relocation.
The park was established to protect the spheres from erosion and private collection after they were uncovered by clearing and natural weathering.
The geological structure of the surrounding hills suggests the area was once part of a much larger marine environment millions of years ago.
The Zavidovići Stone Spheres in the village of Grab are one of the world's few documented clusters of naturally occurring or megalithic stone spheres. Located in a geologically unique park, the site features dozens of spherical stones of varying diameters, with the largest specimens exceeding one meter in width. While geologists often attribute the formation to concretions resulting from volcanic activity or sediment precipitation, their high degree of sphericity and specific mineral composition remain subjects of local debate. The park is integrated into a small, privately managed landscape that includes trails winding through wooded terrain. The site has gained recognition as a site of interest for those studying anomalous geological formations in the Balkans. Visitors can view the spheres in their excavated states, with many remaining partially embedded in the surrounding rocky slopes.
The large, fully excavated sphere near the entrance gate provides the best scale perspective for photography.
Wear sturdy, waterproof hiking boots as the terrain can be muddy and uneven.
Visit during or shortly after a rain shower to see the texture and mineral details of the stone spheres more clearly.
Bring mosquito repellent, as the forested area is prone to insects during warmer months.
Attempting to visit during heavy winter snowfall, as the access roads become difficult to navigate.
Accessible year-round, but outdoor trails may be restricted during severe weather conditions.
Do not climb or sit on the spheres to prevent surface degradation; refrain from removing small stone fragments as souvenirs.
