Far beneath the ruins of Europe's glorious civilizations lies an even more ancient world when dinosaurs were kings. For millions of years their bones lay hidden, preserved in a gloomy primeval swamp. But a new age of discovery dawned that would bring dinosaurs back to life when science gives birth to the greatest giants to ever walk the earth. From a 12th century fortress in the south of France, one of today's foremost French palaeontologists sets out to try to solve a mystery posed nearly 150 years ago. It is here that one of the largest dinosaur nesting sites in the world was found. Of the hundreds of eggs that have been uncovered, all are broken, suggesting they'd hatched. But no one knows what creature laid them.