Watch Attenborough and the Mammoth Graveyard for Free: How to Stream the Movie Online at 123Movies. . Sir David Attenborough joins an archaeological dig uncovering Britain's biggest mammoth discovery in almost 20 years. In 2017, in a gravel quarry near Swindon, two amateur fossil hunters found an extraordinary cache of Ice Age mammoth remains and a stone hand-axe made by a Neanderthal.