Whatever you make of the pyramid claim, the hill itself is worth the climb. The summit holds the genuine medieval ruins of the old town of Visoki, the seat of the Bosnian kings, with sweeping views over the valley and the surrounding peaks.
A path from the visitor centre at the base climbs through forest in around an hour. The "excavations" — terraces and stone slabs unearthed by the Osmanagić foundation — are clearly signposted along the way, and you can decide for yourself.