14 Mysterious Landmarks That Science Still Can't Fully Explain

9. The Stone Circles of Senegambia (Gambia/Senegal): Ancient Ritual Enigma

Scattered across a 60-mile wide band along the Gambia and Senegal rivers lie over 1,000 megalithic stone circles, some containing hundreds of stones up to 10 tons each. Dating from the 3rd century BCE to the 16th century CE, these UNESCO World Heritage sites are believed to be burial mounds, yet the precise methods of quarrying, transporting, and arranging these massive laterite pillars remain largely unexplained. Their sheer number and the sophisticated astronomical or ceremonial alignments observed in some circles continue to puzzle archaeologists, hinting at a complex ancient West African culture whose practices are still shrouded in mystery.