The first megaliths were built in what is now?

The first megaliths were built in what is now Western Europe, particularly in regions such as Brittany in France and the British Isles, including sites like Stonehenge and the dolmens of Ireland. These structures date back to the Neolithic period, around 4000 to 2500 BCE, and served various purposes, including ceremonial and burial functions. The construction of megaliths reflects the social and cultural practices of early agricultural societies in these areas.