Megalthic structures are large stone constructions built by ancient cultures, often for ceremonial or religious purposes. These structures can include stone circles, dolmens, and menhirs, showcasing the engineering skills and social organization of the societies that created them. They are typically made from massive stones, some weighing several tons, and are found in various parts of the world. These structures often hold significant archaeological and cultural value, providing insights into the beliefs and practices of early humans. Notable examples include Stonehenge in England and the Carnac stones in France, which continue to intrigue researchers and visitors alike.