The Lego brick was invented in Billund, Denmark, in 1958 by Godtfred Kirk Christiansen.

Lego were special as the bricks were designed in such a way that they could be stacked and linked with each other in countless combinations.

The son of the inventor, Kjeld Kirk Kristiansen, spoke to Witness about his family's extraordinary business.

Witness: The stories of our times told by the people who were there.