Graham Hancock goes on a global quest, from Cambodia to Egypt, to trace the remains of a lost civilisation that passed on its legacy to ancient cultures all around the world.

From the Nazca lines in Peru, via the pyramids at Giza to the Hebridean settlement of Callanish comes evidence that our ancestors could see how the stars, sun and moon moved and measure annual changes.

The mysterious statues of huge heads on Easter Island have perplexed scientists for hundreds of years. Why did the inhabitants of a remote, tiny Pacific island carve and place such elaborate statues?