18 Monuments That Were Built for Unknown Purposes

Some ancient monuments were constructed with precision and scale, yet their original purpose remains a mystery.

Sophia Zapanta
November 17, 2025
5 min read

18 Monuments That Were Built for Unknown Purposes — Diego Delso on Wikimedia Commons

Across the globe, civilizations built monuments that still puzzle historians and archaeologists. Despite extensive study, many lack clear explanations for why they were created or how they were used. These enigmatic structures offer glimpses into unknown cultural, religious, or scientific practices of the past.

1. 1. Stonehenge, England

Stonehenge is a prehistoric stone circle that was built thousands of years ago. Its massive stones are arranged in an astronomical alignment, yet the exact purpose remains unclear. Some theories suggest ritual, burial, or calendar functions. Scholars continue to debate its original meaning.

2. 2. The Great Pyramids of Giza, Egypt

While tombs for pharaohs are the accepted explanation, some aspects of the pyramids’ construction remain unexplained. The precise alignment and enormous stone blocks raise questions. How ancient Egyptians moved such massive stones is still debated. Some suggest hidden purposes beyond burial.

3. 3. Carnac Stones, France

Thousands of standing stones stretch across Brittany. No written records explain why they were placed in straight lines or patterns. Some think astronomical or ceremonial purposes are likely. Others argue they may have been markers of lost rituals or events.

4. 4. Göbekli Tepe, Turkey

Göbekli Tepe is older than Stonehenge and was built by hunter-gatherers. Its massive carved pillars are arranged in circles, yet the purpose is unknown. Some propose religious or symbolic uses. Its complexity challenges assumptions about prehistoric society.

5. 5. The Moai Statues, Easter Island

These enormous stone heads are placed on ceremonial platforms across the island. The purpose of their construction and transportation is still debated. Some think they honor ancestors or chiefs. The exact societal function remains a mystery.

6. 6. The Nazca Lines, Peru

These geoglyphs stretch across deserts and form massive patterns. They can only be fully seen from above. Their meaning — religious, astronomical, or symbolic — is still uncertain. Researchers continue to study why ancient people created them.

7. 7. The Great Zimbabwe Ruins, Zimbabwe

Massive stone walls and towers were built without mortar. Their original function is unclear, with theories ranging from royal residence to religious center. Archaeologists debate the social organization required for construction. Many details about daily life remain unknown.

8. 8. The Temple of the Giants, Mexico

Located in the Yucatán, this ancient site includes massive stone blocks. Its exact purpose is not documented. Some suggest ceremonial or astronomical use. The monument remains largely enigmatic.

9. 9. Sacsayhuamán, Peru

Sacsayhuamán features enormous stones fitted together with remarkable precision. The purpose of its construction is uncertain. Some believe it had military, ceremonial, or astronomical functions. Its true meaning has been lost to time.

10. 10. Newgrange, Ireland

Newgrange is a passage tomb aligned with the winter solstice sunrise. While burial is one function, its ceremonial or astronomical significance remains debated. The skill required to build it shows advanced planning. Its full purpose is still unknown.

11. 11. Yonaguni Monument, Japan

This submerged stone formation off Japan’s coast appears carved or shaped. Its origin and purpose are unclear. Some argue it’s natural, while others think it was an ancient structure. The debate continues among researchers.

12. 12. The Hypogeum of Ħal-Saflieni, Malta

This underground structure is carved from rock on multiple levels. Its original use is uncertain, with burial or ritual theories proposed. Some carvings suggest spiritual or ceremonial functions. Much of its story remains a mystery.

13. 13. Baalbek Megaliths, Lebanon

Some stones weigh over a thousand tons, forming part of this Roman-era complex. How they were moved and why such massive blocks were needed is still debated. Ritual or ceremonial uses are suggested. The true original purpose remains uncertain.

14. 14. The Oracle of Delphi, Greece

While Delphi was a religious center, the purposes of some structures are unclear. Certain altars and platforms lack a clear historical explanation. They may have been used for ceremonies, divination, or unknown rituals. Archaeologists have not confirmed all functions.

15. 15. The Pyramids of Caral, Peru

Caral is one of the oldest cities in the Americas, with pyramid-like structures. Their exact purpose remains unknown. They may have been ceremonial, residential, or symbolic. The lack of records leaves their function speculative.

16. 16. Puma Punku, Bolivia

Puma Punku features massive stone blocks with precise cuts. The original purpose of this complex remains a mystery. Some suggest ritual, astronomical, or engineering significance. Its construction techniques remain unexplained.

17. 17. The Longyou Caves, China

These artificial caves are carved from solid rock with no clear purpose. How and why they were built is still unknown. Some believe ceremonial, storage, or defensive uses. The scale and precision continue to puzzle researchers.

18. 18. The Medinet Habu, Egypt

Certain sections of Medinet Habu show construction that may not match known functions. Temples and monuments include mysterious carvings and structures. Their ceremonial or symbolic significance is debated. The original purpose of all features is still unclear.