Almanac of the Gods
Bosnian Pyramids (Visočica Hill)
Photo: Mhare · CC BY-SA 4.0 · cropped and resized

Place No. 28 of 44

Bosnian Pyramids (Visočica Hill)

Bosnia and Herzegovina · 43.977° N · 18.176° E

A hill in central Bosnia looks so much like a pyramid that one man has spent twenty years digging tunnels to prove it is one.

Height above the town
about 213–220 m
Claimed age of the 'pyramids'
about 12,000 to 34,000 years (per Osmanagić)
Claimed age of the stone spheres
about 100,000 years (per Osmanagić)
Ravne tunnel network
several kilometers claimed; about 4 km (2.4 miles) cited
Medieval town first recorded
1355
Visitors in the first four years
more than 400,000 (as of 2009)
Distance from Sarajevo
about 30 km

What it is

Visočica is a steep, oddly regular hill that rises above the town of Visoko, about 30 km northwest of Sarajevo in Bosnia and Herzegovina. Seen from the right angle, its faces look almost flat and its top comes to a point. In 2005 Semir Osmanagić, a Bosnian-born businessman living in Houston, announced that it was not a hill at all but the largest pyramid on Earth, which he named the Pyramid of the Sun.

Osmanagić went on to rename several nearby hills as the Pyramids of the Moon, the Dragon, Love and the Earth. He set up a foundation, began excavations, and opened a network of passages near the village of Ravne that he says are ancient tunnels linking the pyramids. Large stone balls found in the region became part of the story too. He has dated the complex to anywhere from about 12,000 to more than 30,000 years ago.

The hill already had a real history. On its summit sit the ruins of Visoki, a royal castle town of medieval Bosnia first recorded in a charter of King Tvrtko I in 1355 and abandoned by the early 1500s. Archaeologists worried from the start that pyramid digging would damage this genuine site. Its walls and foundations are the one part of the hill that experts agree people really built, and it deserves protection in its own right.

Geologists and archaeologists reject the pyramid claim. They say Visočica is a natural landform called a flatiron. Even so, the project turned Visoko into a tourist town, drew hundreds of thousands of visitors, and became a regular stop on Ancient Aliens. Tunnel tours, souvenir stalls and meditation sessions now bring steady income to a region still recovering from the war of the 1990s. The site shows how a disputed idea can reshape a real town.

The ancient-alien case

Semir Osmanagić is the main voice for the Bosnian pyramids, and he goes further than most. He argues that Visočica's faces are too straight and its north side too perfectly aimed at true north to be natural. He says the slopes are covered with cast concrete blocks harder than modern concrete, laid by a lost civilization long before the last Ice Age ended. In a 2025 preprint he cites LiDAR scans, Golden Ratio proportions and radio-frequency signals as support.

His larger claim is about energy. Osmanagić says the pyramid emits a beam of energy from its top and that the tunnels under it have healing effects. He has linked the complex to ideas of a 'cosmic internet' carried by special waves. Ancient Aliens presents Visočica in its episode Hidden Pyramids as one of a worldwide family of buried pyramids that mainstream science has overlooked.

The stone spheres are the second pillar of the case. In the 2024 episode Mystery of the Stone Spheres, Osmanagić says Bosnia's stone balls are man-made and about 100,000 years old. He and writer Kathleen McGowan claim the spheres contain an unknown ingredient and were made to channel earth energy. Theorists place them alongside the famous stone balls of Costa Rica as signs of a shared global technology.

Supporters also point to what they see as a pattern of dismissal. They argue that experts rejected the idea before it had been fully tested, and they note that the site keeps drawing volunteers from around the world who report unusual experiences in the tunnels.

What archaeologists say

Geologists say the hill is a flatiron, a common landform made when tilted layers of rock erode into a triangular face. A University of Tuzla team found that Visočica is built of layered clastic sediments laid down naturally in the valley. Robert Schoch of Boston University, himself known for unconventional views on the Sphinx, studied the site in 2006 and found only ordinary conglomerate, clay and sandstone. The 'blocks' are natural slabs of the same rock that crack along regular joints.

Archaeologists are just as firm. The European Association of Archaeologists called the project a cruel hoax on the public, and leading European archaeologists signed a statement warning that state support wasted money and endangered real heritage, above all the medieval town on the summit. No datable construction material, tool marks, workers' settlements or quarries matching a pyramid-building culture have been found.

The stone spheres are natural too. Geologists identify them as concretions, hard balls of mineral cement that grow inside softer sediment and weather out whole. They are found in many parts of the world. Critics also note that the 'perfect roundness' figures used for them were borrowed from studies of the Costa Rican spheres, which are genuinely carved but much younger.

Timeline

  1. 1355King Tvrtko I issues a charter from Visoki, the royal castle town on top of Visočica.
  2. before 1503Visoki is abandoned; by 1626 it appears on lists of deserted towns.
  3. October 2005Semir Osmanagić announces that Visočica is a man-made pyramid and starts digging.
  4. 2006The European Association of Archaeologists and a group of leading European archaeologists publicly condemn the project; geologist Robert Schoch visits and finds natural rock layers.
  5. 2009Smithsonian magazine reports more than 400,000 visitors and over $1 million in donations to Osmanagić's foundation.
  6. 2015Ancient Aliens includes the Bosnian 'pyramids' in its episode Hidden Pyramids.
  7. 2016An 'archaeological park' with tunnel tours and meditation sessions is up and running for tourists.
  8. 2024Osmanagić appears on Ancient Aliens' Mystery of the Stone Spheres, claiming Bosnia's stone balls are man-made.
  9. 2025Osmanagić posts an unreviewed preprint arguing that LiDAR, orientation and 'energy' readings show the hill was built.

Still unanswered

  • How much damage has the digging done to the remains of the medieval royal town of Visoki?
  • Who dug the Ravne tunnels, and when, since some researchers suspect old mining or much later work?
  • Will any of Osmanagić's claims ever be published in a peer-reviewed journal and tested by independent teams?
  • Why has the project kept strong public and political support in Bosnia despite the scientific verdict?

Did you know?

  • The man who named the Pyramid of the Sun is not an archaeologist; he ran a metalworking business in Houston and became fascinated by Maya and Aztec sites.
  • The medieval castle town on Visočica's summit is the reason archaeologists were most worried about the digging.
  • Local shopkeepers say the town went from almost total skepticism to a rough fifty-fifty split as pyramid tourism brought in money.

On Ancient Aliens

  • S09E10 Hidden Pyramids Includes the Bosnian 'pyramids' among the world's supposedly hidden pyramid sites.
  • S20E10 Mystery of the Stone Spheres Osmanagić and Kathleen McGowan claim Bosnia's stone balls are 100,000-year-old man-made objects built to channel earth energy.

Episode numbers follow Wikipedia's episode list; History and some reviewers number a few seasons differently.

Visiting

Getting there. Visoko is about 30 km northwest of Sarajevo, an easy trip by car, bus or organized day tour from the capital.

What you can see. Visitors can climb Visočica on marked paths, see the excavated trenches and the medieval ruins at the top, and take guided tours of the Ravne tunnels in the nearby 'archaeological park'. The project is privately run and presents the pyramid theory as fact.

Tip. Pair the pyramid tour with the medieval ruins on the summit, which are the hill's genuinely old history.

Sources

  1. Bosnian pyramid claims – Wikipedia en.wikipedia.org
  2. Visočica (hill) – Wikipedia en.wikipedia.org
  3. The Mystery of Bosnia's Ancient Pyramids – Smithsonian Magazine (2009) smithsonianmag.com
  4. Whether Real Or A Hoax, Bosnian 'Pyramids' Bringing Concrete Benefits To Town – RFE/RL rferl.org
  5. Multidisciplinary Evaluation of the Pyramid-Shaped Formation near Visoko (preprint, 2025) – EarthArXiv eartharxiv.org
  6. Review of Ancient Aliens 'Hidden Pyramids' – Jason Colavito jasoncolavito.com
  7. Review of Ancient Aliens S20E10 'Mystery of the Stone Spheres' – Jason Colavito jasoncolavito.com
  8. List of Ancient Aliens episodes – Wikipedia en.wikipedia.org
Research notes: what we could not confirm
  • Colavito's Hidden Pyramids review does not say which theorist speaks about Bosnia, so no name is attached to that segment.
  • Colavito labels Hidden Pyramids 'S07E15'; it matches History's S09E10 by title and air date (April 17, 2015).
  • The old entry's S22E6 'Mysterious Monuments' (2026) rerun of the spheres segment was not confirmed.
  • The distance from Sarajevo and the 'about 4 km' tunnel figure are approximate; tunnel length claims vary by source.
  • Colavito notes that the S20E10 spheres material was recycled from a 2013 episode, which was not identified.