This is the world's largest collection of open-air Palaeolithic art (10,000 to 40,000-years-old). And to think it all nearly disappeared under water.

This stretch of valley peppered with 17 kilometres-worth of rock engravings was only rediscovered in the late '80s when government surveyors began scoping out the area for a potential hydroelectric dam. When salivating archaeologists got wind of the Stone Age discovery, a fierce battle ensued to save the valley.