At two-and-a-half hours long, Fritz Lang's 1927 classic Metropolis was considered too long for audiences in the heyday of the cinema and it was cut, re-edited, and re-released.

Now, thanks to the discovery of the 25 minutes of lost footage unearthed in an Argentine museum, Metropolis has been put back together the way the director intended.

Stephen Smith reports.

Broadcast on Thursday 26 August 2010.