Trains: How the railway revolution began in Merthyr Tydfil
The origins of your morning commute began high in a Welsh valley in 1804, a TV historian says.
In Merthyr Tydfil, the Elon Musks and Mark Zuckerbergs of the 19th Century bet on whether you could make a rail locomotive move on its own.
Dan Snow said this was the revolution which began the invention of rail travel.
Video edited by Nathan Aviss, BBC News
