Anatomically modern humans are thought to have arrived in South Asia 73-55,000 years back, though the earliest authenticated human remains date to only about 30,000 years ago. Nearly contemporaneous Mesolithic rock art sites have been found in many parts of the Indian subcontinent, including at the Bhimbetka rock shelters in Madhya Pradesh. Around 7000 BCE, the first known Neolithic settlements appeared on the subcontinent in Mehrgarh and other sites in western Pakistan. These gradually developed into the Indus Valley Civilisation, the first urban culture in South Asia; It flourished during 2500–1900 BCE in Pakistan and western India. Centred around cities such as Mohenjo-daro, Harappa, Dholavira, and Kalibangan, and relying on varied forms of subsistence, the civilisation engaged robustly in crafts production and wide-ranging trade.