They are locally known as "muniyara", derived from muni (hermit or sage) and ara (dolmen).[36] Rock engravings in the Edakkal Caves, in Wayanad date back to the Neolithic era around 6000 BCE.[37][38] Archaeological studies have identified Mesolithic, Neolithic and Megalithic sites in Kerala.[39] The studies point to the development of ancient Kerala society and its culture beginning from the Paleolithic Age, through the Mesolithic, Neolithic and Megalithic Ages.[40] Foreign cultural contacts have assisted this cultural formation;[41] historians suggest a possible relationship with Indus Valley Civilization during the late Bronze Age and early Iron Age.[42]