John Hurt narrates the facts behind the discovery of a huge dinosaur nesting site in modern day Patagonia. Fossilised remains show Argentinosaurus laid tens of thousands of eggs in a 15 km nesting site used for hundreds of thousands of years. The hatchlings, if they survive, will grow at an incredible rate. Over a 40 year life span Argentinosaurus can grow from 4 kg to 75 tons!

Presented by BBC Earth's Planet Dinosaur series.